
Class. J__ 



REPORT 



BOUNDAEY COMMISSION 



SURVEY AND REMARKING OF THE BOUNDARY BETWEEN 

THE UNITED STATES AND MEXICO 

WEST OF THE RIO GRANDE, 

1891 TO 189G. 



PARTS I AKD n. 



FART I. 
REPORT OF THE INTERNATIONAL COMMISSION. 

FART II. 
REPOR'T OE THE UNITED STATES SEdlON. 



WASHINGTON: 

GOVERNMENT PRINTING OFFICE 






25425 



^^ 



1899 



X^/"irASH\*^ 



MESSAGE 



PRESIDENT OF THE UNITED STATES, 

TRANSMITTING 

A REPORT FROM THE SECRETARY OF STATE, ACCOMPANIED BY THE REPORT OF THE 
UNITED STATES BOUNDARY COMMISSION, PURSUANT TO THE CONVENTION BETWEEN 
THE UNITED STATES AND MEXICO OF JULY 29, 1882, TOUCHING THE RE-MARKING OF 
THE BOUNDARY LINE BETWEEN THOSE TWO COUNTRIES WEST OF THE RIO GRANDE. 



To the Congress of the Vnitid States: 

I transmit herewith a report from the Secretary of State, accompanied by the report of the 
United States Boundary Commission, pursuant to the convention between the United States and 
Mexico of July 29, 1882, touching the re-marliiug of the boundary line between those two countries 
west of the Rio Grande. 

I urge that provision be made for the immediate printing of a suflicient supply of this 
valuable document. 

William McKinley. 

Executive Mansion, 

Washington, April 26, 1897. 

Tile President: 

I transmit herewith the report of the United States Boundary Coin mission under the conven- 
tion between the United States and Mexico, concluded July 29, 1882, which provided for an 
international boundary survey to relocate the existing frontier line between the two countries 
west of the Rio Grande. 

Tiie commissioners on the part of the United States were Col. J. W. Barlow, Corps of 
Engineers, U. S. A.; Capt. D. D. Gaillard, Corps of Engineers, U. S. A., and Mr. A. T. Mosniaii, 
of the United States Coast and Geodetic Survey, Treasury Department. Tliey have discharged 
their work in a creditable and satisfactory manner, as will be further seen by the report and its 
several accompaniments. 

Inclosing as a part of the record in the case a copy of a letter from the commissioners, dated 
November 25, 189G, the subject is respectfully submitted for your consideration. 

Respectfully submitted. 

John Shekman. 

Department of State, 

Washington, April 22, 18'.>7. 



List of accompaniments. 
Report, 3 volumes. 
Maps, 1 voluiiie. 
EngraviDgs, 1 volume. 
Letter of November 25, 189(5, from the commissiouers to the Secretary of State, with its accompaniments. 



4 united states and mexican boundaey. 

Department of State, 
International Boundary Commission, 

United States and Mexico, 
Washington, B. C, November 25, 1896. 

Sir: The coniiiiissioiiors on tlie jiart of tlie United States have the honor to submit herewith 
their final report on the survey and remarking of the boundary between the United States and 
Mexico west of the Rio (iraiide, pursuant to tlie convention between the United States and 
Mexico of July 29, 1.SS2, revived by the convention of February 18, 1889, and continued until 
October 11, 1896, by that of April 21, 1894. 

The report consists of the following: 

First. The report of the joint commission (in triplicate, one copy being in the Spanish 
language), dated August 14, 1896. 

An atlas, bound in leather, containing 19 sheets of the boundary map. 

One volume bound in leather, of 300 illustrations, showing views of the monuments and 
scenes adjacent to the boundary. 

Second. The report of the United States section of the commission, consisting of 2 volumes 
(in duplicate) arranged in 10 chapters, including appendixes. 

One atlas, bound in leather, containing 5 sheets of profile and 2 sheets, index map. 

Two atlases (three retained by tlie commissiouers), each containing 19 sheets of the boundary 
map, 5 sheets of profile, and 2 sheets, index map, showing the adjacent country. 

Two volumes of illustrations (seventeen retained by the commission for distribution to the 
libraries of the War Department, the .Military Academy at West I'oint, and the principal 
employees of the Survey. 

Sixteen volumes (four sets) of the ])hotographs and about GOO negatives were jireviously sent 
to the Department. 

Inclosed herewith is a list of cojiperplates, electrotypes, original maps, survey records, etc., 
which are transmitted in connection with the report. 

In presenting this report of the work upon which the commission has been engaged during 
the past four years we beg leave to express our ai>preciatiou of the uniform support aud kind 
consideration received at all times from the Department, without which our labors would have 
been much more difiBcult. 

We would also put on record the fact that throughout the many trying and often delicate 
conditions of an international character, which have of necessity arisen during the progress of 
the work, our associates of the Mexican commission have invariably shown a spirit of fairness 
and courtesy which has always rendered possible the satisfactory solution of every jierplexiug 
question. 

To SeHor Jacobo Hlanco, engineer in chief of the Mexican section, who is a thorough Knglish 
scholar, special thanks are due for valuable assistance in translating ;.nd interpreting, rendering 
the employment of a special translator unnecei*sary. 

This report may now be laid before the President with a view to tlie tiansmissiou thereof to 
Congress. 

With highest respect, your obedient servants, 

J. W. Barlow, 
Colonel of Entiineers, U. S. A., 

D. D. Gaillard, 
Captain of Enaimrrs, U. S. A., 
A. T. MoSMAN, 
Assistant, Coaxf and Geodetic Survey, 

Commissioners. 

The Skoretarv of State, Wasliinyton, l>. C. 



UNITED STATES AND MEXICAN BOUNDARY. 5 

List of hoxix mill rolls {with i numeration of mntents) transmiUml to thi- Deparlnunl of Stale iiilli thf nport of tin: 
International Bonnilarji Commission, Unitid States and Mexico, icest of the l!io t:rinidr. 

Six boxes loutaining 300 half-tone coppeiphitea of illustrations to accompany joint ri'poi t. 

One rack for copperplate holders. 

Twelve boxes (copperplate holders) containing copperplates of map sheets Nos. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19,25, 
and 26, each box being marked ''Mexican bonndary «est of the Rio Grande," with its plate number. 

Ten boxes (electrot.ype-plate holders) containing electrotype plates of map sheets Nos. 2, 4, 6, 8, 10, 12, 14, IK, 18, 
and 19a, each box being marked " Mexican boundary west of the Rio Grande," with its plate number. 

One roll containing 220 photolithographs, 44 sets, of the profile sheets, 90 illustrations for report of United 
States section, Chapter IV, and 5 atlas title sheets. 

One roll containing 17 original maps, being sheets Nos. 1, 2, r<, (i, 7, 9, 1 1, 14, is, 19, 20, 21, 22, 23, 24, 25, nu<l 2t). 

One box. No. 1, containing astronomical records, as follows: 

6 volumes 8vo., original latitude observations. 
5 volumes 8vo., original azimuth observations. 

9 volumes 8vo., original horizontal directions (trians;ul.ili(in ). 

2 volumes 8vo., original horizontal angles. 

2 volumes 8vo., original magnetic observations. 

8 volumes 8vo., original miscellaneous records. 

1 volume 4to., original description of stations. 

7 volumes 8vo., duplicate tangent record. 

2 volumes 8vo., duplicate heliotrope experiments; also astronomical and geodetic compntatiims and manu- 
script copies of Mr. .1. F. Hayford's astronomical report and liui- report. 

One box, No. 5, containing — 

5 volumes original journal. 

1 volume original tangent record, parallel 31'- 47' and mcridiiin section. 
1 volume original tangent record, parallel 31' 20 . 

1 volume original tangent record, parallel 31"^ 20' .and California nziniuth line. 
7 volumes original tangent record, Sonora azimuth line. 

2 volumes original heliotrope experiments. 

4 volumes original tangent measurements, parallel 31"^ 47 . 
1 volume original t.angent measurements, meridian section. 
1 volume original tangent measurements, meridian soctimi nnd parallel :!1- 20'. 

7 volumes original tangent measurements, parallel 31 20'. 

volumes original tangent measurements, Sonora aziniuMi line. 

4 volumes original tangent measurements, California. 

1 volume original tangent remeasurements, meridian section and par.allel 31 2(1'. 

2 volumes original level records, jiarallel 31 47'. 

1 volume original level records, parallel 31 47' and meridian section. 
1 volume original level records, meridian section and parallel 31' 20 . 

8 volumes original level records, par.allel 31 20'. 

6 volumes origin.al level records, Sonora azimutli line. 

5 volumes original level records, California azimuth line. 

1 volume original topographical .sketches, parallel 31 47 . 

1 volume original topographical sketches, parallel 31 47' aixl nieridi.iu seciloii. 

3 volumes original topographical sketches, par.allel 31 20 . 

3 volumes original topographical sketches, Sonora azimuth line. 

1 volume original topographical sketches, California. 

13 volumes original topographical records, piirallel 31 47 . 

2 volumes original topographical ]ei(irds, parallel 31 47 and uieiidian sectimi. 

3 volumes original topographical iccdiils, ineridiau section. 
45 volumes original topographical records, parallel 31 20 . 

41 volumes original topographical records, Sonora azinnitli line. 
19 volumes original topographical records, California. 

6 volumes original record monument location. 
2 volumes original record monument elevation. 

One box, No. 24, containing correspondence of the United States section of the commission (letters received, 
letters sent). 



V 



P^TIT I. 

R E P ( ) R T 

OF TUB 

INTERNATIONAL BOUNDARY COMMISSION, 
UNITED STATES AND MEXICO, 

1 8 9 1 - 1 S 9 G . 



CONTENTS OF REPORT OF THE JOINT COMMISSION. 



Section 1 : Pagu. 

Article V of trraty of (iiiadahiiie HiilalKo 11 

Section 2: 

Treaty of Deceiiilier 30, 1S53, and account of work of the original comiiiission nuder its iirovisions 12 

Section 3: 

Convention of July 29, 1882 13 

Section 4: 

Convention of February 18, 1889 11 

Section 5: 

Appointment of joint commission, niulcr this convention, -nitU copies of the commissions of its members 

and their instructions from tlieir respective Governments l.">-l(i 

Section 6: 

Plan of operations agreed upon by the engineers-in-chief of the two .lectious for snrveyinj; and raarkiiif; 

the bonndary 17 

Agreement in regard to size and sliape of the monuments and the method of erection 18-19 

Section 7: 

Journal of the proceedings of the joint commission to October 1, 1891 20-23 

Section 8: 

Astronomical detenninations — 

Longitude 23 

Latitude 21 

Azimuth 24 

Longitude results by United States section 25 

United State.s latitude observations and table of results 25 

United States azimuth observations and table of results 2G 

Mexican observations for longitude and table of results 27 

Mexican observations for latitude and tal>Io of results 27 

Mexican observations for azimuth and table of results 27-28 

Final results for latitude, by both sections 28 

Section 9 : 
Geodesy — 

Tables of United States and Mexican tangents, parallel of 31^ 47' 29-30 

Tables of United States and Mexican distances, meridian section 30 

Tables of United States and Mexican tangents, parallel of 31° 20' 30-31 

Tables of United States and Mexican distances, Sonera azimuth line 32 

Tables of United States and Mexican distances, California azimuth line 32 

Operations of the Mexican section 32 

Operations of United States section 33 

Joint operations 33 

United States triangulation n<^ar Monument No. 1 33 

Mexican determination of longitude of Monument No. 1, by flashes 33 

Triangulation at Nogales 33 

Triangulation near Yuma 33 

Limits of diiference of United States and Mexican results for distance and offsets 34 

Table of final distances on parallel 31^ 47' 34-35 

Table of final distances on meridian section 35 

Tal)lo of final distances on parallel 31'^ 20' 36-37 

Table of final distances on Sonera azimuth line 37-38 

Table of final distances on California azimuth line 38-39 



10 UNITRD STATES AND MEXICAN HOUNDAKY. 

Sfx'Tion 10: 

.Mt'tlioda used in the original siirvny lS49-lXo()— Page. 

Astronomic:!] iletfrrainsitions of tlie original snrvcy 39-40 

Method of ninninff the lino on tho ground 40 

Comparison of distances determined hy the original snrvey, 1849-1856, with those obtained hy the 

present commission 41-16 

Distances on parallel Sl"^ 47' 41 

Distances on meridian section 41 

Distances on parallel 31" 20' 43 

Distaiices on Sonora line 44 

Distances on California line 4(5 

Measnres of the 20 miles from junction of the Gila and Colorado to the initial point in the Colorado . . 45 
Differences V)etwoen the determinations of longitude by the original commission and those of the pres- 
ent survey 46-47 

Original ninminients 47-49 

Section 11 : 

Topography- 
Topography of United States section 49-50 

Tojiograjjhy of Mexican section 50 

Section 12: 

Journal of joint commission from October 11, 1895, to February 24, 1896 51-52 

Section 13: 

Construction of maps of the boundary 53 

Table of mean latitudes of astronomical stations 53 

Table of mean latitudes and longitudes of monuments on parallel 31' 47' 54 

Table of mean latitudes and longitudes of monuments on parallel 31 " 20 ' 54 

Table of mean latitudes, longitudes, and azimuths, and distances on Sonora line 55 

Table of mean Latitudes, longitudes, and azimuths, and distances on California line 55 

Journal of proceedings at final meeting of the International Commission, August 14, 1896 55-56 



LIST OF ILLUSTRATIONS. PAET I. 



Page. 

1. View on wagon road cast of Nogales Froutispiece of Volume. 

2. Custom House, El Paso 12 

3. Type of New Iron Monument 18 

4. Camp No. 1, Rio Gnmde 20 

5. Observatory at Monument No. 204, Arizona 28 

6. Mexican Consulate, Nogales 32 

7. View in Yuma, Ariz .S:t 

8. Old Mission, San ,Io86 de Tnmaeacori 44 

9. Old Mission, San Xavier del Bao 51 



REPORT OF THE JOINT COMMISSION. 



SKCTIOX 1. 

The bouiulary between the Republies of the ITnited States .iiid Mexico was defined by the treaty 
of Guadahipe Hidalgo, and subsc(iuent)y modified by that luiown as the Gadsden treaty, or treaty 
of La Mesilla. 

The first of these was conchided and signed at the city of (inadalupe Hidalgo, on the 2d of 
February, 1848, by the dnly authorized i)lenii)otentiaries of the resi)ective Governments. Tiiese 
were, on the part of the United States, Mr. Nicholas V. Trist, and on the ]>art of Mexico, Senores 
Bernardo Oouto, Miguel Atristain, and Luis G. Guevas. 

Following is a copy of Article V of the treaty of Guadalup*^ Hidalgo, which relates specially 
to I he boundary between the two countries : 

AuTiCLK V. The bouiulary line between tlio two Rcpnblics shall commence in the Gulf of irexicn, throe leagues 
from land, opposite the mouth of tlie Kio Grande, otherwise called Rio Hr.avo del Norte, or opposite the mouth of its 
deepest branch, if it should have more than one branch emptying directly into the sea; from thence np the mid<lle 
of th.at river, following the deepest channel, where it has more than one, to the point where it strikes the southern 
boundary of New Mexico; thence westwardly along the whole scmthern boundary of N6w Mexico (which runs north 
of the town called Paso) to its western termination ; thence northward along the western line of New Mexico, until it 
intersects th(^ first branch of the river Gila (or if it should not intersect any branch of that river, then to the point 
on the said line nearest to such l)ranch, and thence in a direct lino to the same) ; thence down the middle of the said 
branch and of the said river until it empties into the Rio Colorado; theuco across the Rio Colorado, followiuf; the 
division line between Upper and Lower California, to the Pacific Ocean. 

The southern and western limits of New Mexico mentioned in this article are those laid down in the map 
entitled "Map of the United Mexican States, as organized and defined by various acts of the Com/ress of said Republic, 
and constructed according to the best authorities. Revised edition. Puhlished at Xew York in 1S47 by J. nislurneU." 
Of which map a copy is added to this treaty, bearing the signatures and seals of the undersigned plenipoten- 
tiaries. And, iu order to preclude all difficulty in tracing upon the ground the limit separating Upper from 
Lower California, it is agreed that the said limit shall consist of a straight lino drawn from the middle of the 
Rio Gila, where it unites with the Colorado, to a point on the coast of the Pacific Ocean, distant one marine league 
due south of the southernmost point of the port of San Diego, according to the plan of said port made in the year 
1782 by Don .Juan Pantoja, second sailing master of the Spanish fleet, and published at Madrid in the year 1802, in 
the Atlas to the voyage of the schooners Sutil and Mexicanu, of which plan a copy is hereunto added, signed and 
sealed by the respective plenipotentiaries. 

In order to designate the boundary line with due precision, upon authoritative maps, and to establish upon the 
gronnd landmarks which shall show the limits of both Republics, as described in the present article, the two 
Govirnments shall each appoint a commissioner and a surveyor, who, before the expiration of one year from the 
date of the exchange of ratifications of this treaty, shall meet at the port of San Diego, and proceed to run and 
mark the said liouudary in its whole course to the mouth of the Rio Bravo del Norte. They shall keep journals 
and nuike out plans of their operations; and the result agreed upon by them shall bo deemed a part of this treaty, 
and shall have the same force as if it were inserted therein. The two Governments will amicably agree regarding 
what may lie necossniy to these persons, and also as to their respective escorts, should such be necessary. 

Tlie boundary line established by this article shall bo religiously respected by each of the two Republics, and no 
change shall ever bo made therein except by the express and free consent of both nations, lawfully given by the 
General Government of each, in conformity with its own Constitution. 

For the purpose of carrying into effect the requirements contained in the above article, 
commissioners and surveyors were appointed by the two Governments. Those for the United 
States were Col. John B. Weller, commissioner, and Mr. Andrew B. Gray, surveyor. The Mexican 
Government appointed Gen. Pedro Garcia Coude, commissioner, and Senor Jose Salazar Illarregui, 
surveyor. 

Under the direction of these commissioners the initial point of the boundary between Upper 
and Lower California was established on the Pacific coast and marked by a substantial monument. 



12 UNITED STATES AND MEXICAN BOUNDARY. 

A similar (loteniiii.atioii was made at tlie eastern extremity of this line, at the junction of the 
(rila and Colorado rivers, where another monument was plac^ed. Between these the line was run 
and marked with five iutennediate monuments. Astronomical observations were also made in 
the vicinity of Paso del Norte, which were afterwaids used in establishing the initial point on the 
Rio Grande, in accordance with the treaty (»f December 30, 18.53. 

A more detailed account of the scientific work above referred to will be found in section 10 of 
this report. 

SECTION 13. 

By the treaty of December ."JO, 1853, that part of the boundary between the Rio Grande and 
the Itio Colorado, as previously defined, was materially changed. Article I of that treaty being 
as follows: 

AuTici-E I. The Mexican Republic iigrci's to designate the following .as her true limits Avith the United States 
for the future: Retaining the sauie dividing line between the two Califorui.is as already defined and established, 
.according to tlie fifth article of the treaty of Ouadalupe Hidalgo, the limits between the two Republics shall be as 
follows: Heginning in the (!iilf of Mexico, three leagues from land, opposite the month of the Rio Gr.ande, .as 
provided in the iiftli :irticlc of the treaty of Gn.adalupe Hidalgo; thence as defined in the said .article up the middle 
of that river to the point where the parallel of 31^ 47' north Latitude crosses the s.ame; thence due west 100 miles; 
thence south to the p.arallel of 31'^ 20' north latitude; thence along the said p.arallol of Zl"^ 20' to the one hundred 
and eleventh meridian of longitude west of (iroenwich; thence in a straight line to a point on the Colorado River 
20 English miles below the junction of the Gila and Colorado rivers; thonce up the middle of the said river 
Color.ado until il- intersects the present line between the United States and Mexico. 

For the performance of this portion of the treaty, e.ach of the two Governments shall nominate one eommis- 
Bioner, to the end that, by common consent, the two thus nominated, having met in the city of Paso del Noi-te, three 
months after the exchange of the ratiPcations of this treaty, may proceed to survey .and mark out upon the laud 
the dividing line stipulated by this article, where it shall not have already been surveyed and established by the 
mixed commission, according to the tre.aty of Guadalupe, keeping a journ.al and making proper plans of their 
operations. For this purpose, if they should judge it necessary, the contracting parties shall be .at liberty each to 
unite to its respective commissioner scientific or other assistants, such as astronomers and surveyors, whose 
concurrence shall not bo considered necessary for the settlement and ratification of a true line of division between 
the two Republics; that line shall be .alone established upon which the commissioners m.ay fix, their consent in this 
p.articnlar being considered decisive and .an integral part of this treaty, without necessity of ulterior ratification or 
approval, and without room for interpretation of .any kind by either of the parties coutr.acting. 

The dividing line thus established sh.all, in all time, be faithfully respected by the two Governments without 
.any v:iriatiou therein, unless of the express and free consent of the two, given in conformity to the principles of the 
law of nations, and in .accordance with the constitution of e.ach country, respectively. 

In consequence, the stipulation in the .^)th article of the treaty of Gn.adalupe upon the boundary line therein 
descrilied is no longer of .any force, wherein it may conflict with th.at here established, the said line being considered 
annulled and abolished wherever it may not coincide with the present, and in the s.ame manner remaining in full 
force where in accordance with the same. 

In compliance with the terms of the above article, the survey of the new line was carried on, 
and, after .some changes in the personnel of tlie original commission, the whole boundary, including 
the i>art formed by the Rio Grande and the Rio Colorado, was duly established. 

The direction of the California boundary was not changed, but its eastern terminus was fixed 
at the jioiiit where it crossed the channel of the Rio Colorado, about G miles (10 kilometers) west 
of the Gila. The inoniinient previously erected near the junction now being unnecessary, was 
utilized to mark a point on the new Arizona and Sonora line near its western terminus. 

In addition to the G monuments, which remained to mark the California boundary, the com- 
missioners reported that 47 had been placed along the line from the Rio Grande to the Colorado. 
These were all shown ujion the Mexican copy of the joint map, while upon the American copy but 
46 were represented. Of these 53 boundary marks, alleged to have been placed along the entire 
line west of the Rio Grande, the majority were but rude piles of stone; a few only being of a 
durable character, and provided with proper inscriptions, while the intervals between them were 
found to be in some cases as great as 20 or 30 miles (32 or 48 kilometers), and in one instance 101 
miles (1G3 kilometers). The durable monuments were, notably, Nos. 1, 2, and 3 on parallel 31° 47', 
and those marking the extremities of the meridian section, the latter and No. 1 being of dressed 
stone laid in mortal". 

A full account of the methods used in establishing the old uiouunients, and their character, 
will be found in section 10 of this report. 




U. S. CusToM-HorsK, 1-; 



UNITED STATES AND MEXICAN BOUNDARY. 13 

SECTIOIir 3. 

In later years settlers entered upon the lands adjacent to tlie boundary, and mines were 
discovered in its immediate vicinity. Difficulties tlien arose regarding the exact location of tbe 
line, it being charged that some of the original marks had been destroyed or removed. 

To put ail end to these difficulties a convention between the two Governments was concluded 
at the city of Washiugtou, July 29, 1882. Following is a copy of this convention: 

The President of the United States of America on the one hand, and the President of the United States of Mexico 
on the other, being desirous of putting an end to whatever difficulties arise from the destruction or disidaccment of 
some of the monuments erected for the purpose of marking the boundary between the two countries, Lave thought 
proper to conclude a convention with the object of deKuing the manncu' in which the said monuments are to be 
restored to their proper places and new ones erected, if necessary ; to which end they have appointed as their pleni- 
potentiaries, to wit: 

The President of the United States of America, Frederick T. Frelinghuyseu, esquire, Secretary of State of the 
United States of America; and the President of the United States of Mexico, Se.lor Don Mati.as Komero, envoy 
extraordinary and minister plenipotentiary of the United States of Mexico, iu Washington; 

Who, after reciprocal exhibition of their full powers, found in good and due form, have agreed upon the 
following articles : 

Article I. With the object of ascertaining the present condition of the monuments marking the boundary 
lino between the United States of America and the United States of Mexico, established by the treaties of February 
2, 1818, and December 30, 1853, and for determining generally what monuments, if any, have been destroyed or 
removed and may require to be rebuilt or replaced, a preliminary reconnoissance of the frontier line shall be made 
by each Government, within six months from the exchange of ratifications of this convention. These reconnois- 
sancos shall be made by parties >mder the control of officers of the regular army of the respective countries, and 
shall be effected iu concert, iu sach manner as shall be agreed upon by the commanders of the respective parties. 
The expense of each reconnoifcring party shall bo borne by the government in whose behalf it operates. 

These reconnoissance parties shall report to their respective Governments, within eight months from the 
exchange of the ratifications of this convention — 

(a) The condition of the present boundary monuments. 

(h) The number of destroyed or displaced monuments. 

(c) The places settled or capable of eventual settlement, where it may be advisable to set the monuments closer 
together along the lino th.an at present. 

(rf) The character of the now raonuuients re(iuired, whether of stone oi iron, and their number, approximately, 
in each case. 

Akticlk II. Pending the conclusion of the preliminary reconnoiss.ances provided iu Article I, each Government 
shall appoint a surveying party, consisting of an engineer in chief, two iissociates, cue of whom shall be a priictical 
astronomer, aud such number of assistant engineers and associates .as it may deem projier. The two p.arties so 
appointed shall meet at El Paso del Xorte, or at any other convenient place to be .agreed upon, within six months 
from the exchange of the ratifications hereof, and shall form, when combined, an "International Boundary 
Commission." 

Article III. The International Boundary Commission shall be required and have the power and authority to 
set iu their proper places along the boundary line between the United States and Mexico, from the Pacific Ocean to 
the Rio Grande, the monuments heretofore placed there under existing treaties, whenever such monuments shall 
have become displiiced; to erect new monuments on the site of former monuments when these shall have been 
destroyed, .and to set new monuments at such points as nuiy be necessary and lie chosen by joint .accord between the 
two couuuissioner engineers iu chief. In rebuilding anil replacing the old monuments and in providing for new ones 
the respective reports of the reconnoissance parties, provided by Article I, maybe consulted: Proiided, howerer. 
That the distance between two consecutive monuments shall never exceed 8,000 meters, and that this limit may be 
reduced on those parts of the line which are inhabited or capable of habitation. 

Aktkle IV. Where stone shall be found in sufficient abundance the monuments may be of stone, and in other 
localities shall be of iron, iu the form of a simple tapering four sided shaft with pediment, rising above the ground 
to a height of 6 feet, aud bearing suitable inscriptions on its sides. These monuments sball be at least two 
centimeters in thickness and weigh not less than 500 pounds each. 

The approximate number thereof to be required may be determined from the reports of the preliminary 
reconnoissance parties, aud the monuments, properly cast and finished, may Ije sent forward from time to time to 
such spots as the commission may select, to be set in place at the sites determined upon as the work progresses. 

Article V. The engineers iu chief of both sections shall determine, by common consent, whiit scientific 
processes are to be adopted for the resetting of the old monuments and the erection of the new ones, and they shall 
be responsible for the performance of the work. 

(")n commencing operations, each section shall report to its Government the plan of operations upon which 
they shall have jointly agreed ; and they shall fiom time to time submit reports of the jirogrcss m.ade by them in the 
said operations; .and finiilly they shall present a full report, accompanied by the necessary drawings, signed by the 
engineer in chief and the two associate eugim'ers on each side as the official record of the International Boundary 
Commission. 

Article VI. The expenses of e.ach section shall be defrayed by the Government which apiiointed it; but the 
cost of the monuments and of their transportation shall be equally shared by both (iovcrnments. 



14 UNITED STATES AND MEXICAN BOUNDARY. 

Akticlk VII. Whenever the number of thu inoiuniiuiits to be set up Hliall be approximately known as the result 
of tlie labors of tbe preliminary recouuolssance parti.s, the engineers in chief shall prep.arc an estinuite of their cost, 
couveyance, and setting up; .and when such estimate shall have been approved by both Governments, the mode of 
making the payment of the part to be p.iid by Mexico shall be determined by a special arrangement between the 
two Gov<'rnmeiit8. 

AnTiCLE VIII. The work of the International Boundary Commission shall be pushed forward with all expedition ; 
and the two Governments hereby agree to regard the present convention as continuing in force until the conclusion 
of said work, provided that such time does not exceed four years and four months from the date of the exchange of 
the ratifications hereof. 

Article IX. The destruction or displacement of any of the monuments described herein, after the line shall have 
been located by the International Boundary Commission as aforesaid, is hereby declared to bo a misdemeanor, 
])uni8hable according to the justice of the country of the offender's nationality, if he bo a citizen of either the United 
States or Mexico; and if the offender be of other nationality, then the misdemeanor shall be punishable according 
to the justice of either country where he may be apprehended. 

This convention shall be ratified on both sides and the rectifications exchanged at Washington as soon .as 
possible. 

In testimony whereof we have signed this convention in duplicate, in the English and .Spanish languages, and 
affixed hereunto the seals of our arms. 

Done iu the city of Washington this 2yth day of July, in the year of our Lord one thousand eight hundred 
and eighty-two. 

Freu'k T. Fhelinghuvsen. [seal.] 
M. Romero. [seal.] 

Tliu reconnoissauce provided for by this couveution was made iii 1883 iudepeiidoiitly by officers 
of the American and Mexican Goveriimeiits re.spectively, and reports were duly submitted which 
veriaed the necessity of a more detiuitc deniarkatiou of the boundary. 

SECTION 4. 

The convention of 1882 in its further provisions was not carried into effect before the date of 
its expiration, and another conveutioii to revive and continue the same was concluded February 
IS, 1889, between the two Governments. Following is a copy of this convention: 

Convention between the United States of America and the United States of Mexico, to revive the provisions of 
the convention of July 29, 1882, to survey and relocate the existing boundary line between the two countries west 
of the Rio Grande, .and to extend the time fixed iu Article VIII of the said convention for the completion of the work 
in iinestion. 

Whereas the provisions of the convention between the United States of America and the United States of 
Mexico, signed at Washington on the twenty-ninth of July, one thousand eight hundred and eighty-two, to survey 
and relocate the existing boundary between the two (^ouutries west of the Rio Grande, so far as they relate to 
Article VIII of said ccmveution, have not been carried out through delays iu the appointment of the comiui.ssiou 
to undertake the work; 

And whereas, by the additional article to tlie said convention, signed at Washington the fifth of December, one 
thousand eight hundred and eighty-five, the tini.^ fixed iu Article VIII of the said convention of .July 29, 1882, was 
extended for a period of eighteen months from thr, expiration of the term stipulated in said Article VIII. 

And whereas, the said additional pi'riod of time, as so extended, h.as expired Avithout tlie appointment of the 
.commission in (|nestiou, and the said convention has accordingly ceased to be in force pursuant to the iirovisious 
of Article VIII thereof; 

And whereas, it is the wish and understanding of the United States and Mexico tliat the provisions of the said 
convention of .luly 29, 1882, shall be revived and continued in force and ott'ect until the completion of the work for 
which it was originally negotiated, they have appointed for this purpose, their respective plenipotentiaries to wit: 

The President of the United State's of America, Thomas F. Bayard, Secretary of State of the United States of 
America, and 

The I'rcsiilent of the United States of Mexico, Matias Romero, invoy extraordinary ami minister jilenipotontiary 
of the United States of Mexico in Washington, 

Who, after having communicated to each other their respective full powers, found iu good .and due form, have 
agreed ui)on and concluded the following articles: 

Article I. In view of the fact that the origin.al convention of July 29, 1882, between the United States and 
Mexico, providing for tl o resurvey of their boundary line, has lapsed by reason of the failure of the two Govern- 
ments to provide for its further extension before the 3d day of .January, 1889, as contemplated by the additional 
article to that convention, of December .5, 1885, it is hereby mutually agreed and expressly understood by and 
between the contracting parties hereto that the said convention of July 29, 1882, and every article and clause 
thereof, ;ire hereby revived and renewed as they stood prior to January 3, 1889. 

Article II. The time fixed in Article VIII of the convention concluded .at Washington July 29, 1882, between 
the United States of America and the United States of Mexico, to establish an intern.ational boundary commission, 
for the purpose of resurveying and relocating the existing boundary line between the two countries west of the Rio 
Grande, as provided for in said convention, and which was extended for eighteen mouths from the expiration of the 
term fixed in Article Vlll of the said convention of July 29, 1882, is hereby further extended for a period of five 
years from the date of the excliaugi' of ratifications hereof. 



UNITED STATES AND MEXICAN BOUNDARY. 15 

This couveutiou shall be ratified by the contracting parties in conformity with their respective constitutions 
and its ratifications shall be exchanged at Washington as soon as possible. 

In faith whereof we, the undersigned, in virtue of our respective full powers, have signed the present conven- 
tion in duplicate, and have thereunto affixed our respective seals. 

Done at the city of Washington the 18th day of February, in the year of our Lord one thousand eight hundred 
and eighty-nine. 

T. F. Bayard, [seal.] 
M. Romero, [seal.] 
SECTION 5. 

Pur,suaiit to the above convention, and to carry its provisions into eiiect, officers on the part 
of the two Governments were selected as specified in the following letters of appointment: 

Dkpartment ok Statk, Washington, November 13, 1891. 
J. W. Barlow, LiciUcnant-Colonet, Corps of Engineers, U. S. Army. 
David DuB. Gaillard, Lieutenant, Corps of Engineers, U.S. Army. 
A. T. MosMAN, Esq., of the XT. K Coast and Geodetic Survey. 
El Paso, Texas. 

Gentle.men: By designation of the President, you are to constitute the International Boundary Conimissinn on 
the part of the United States, as i)rovided by the treaty with Mexico of July 29, 1882, revived by that of February 
18, 1889, to relocate, lu conjunction with a similar commission appointed by the Government of Mexico, the monu- 
ments marking the boundary lino between the two countries. 

The Department has no instructions to give for the execution of your work beyond referring you to the provi- 
sions of the treaty upon the subject and enjoining upon you the desirability and the necessity of prosecuting your 
labors to completion as rapidly as circumstances will permit. 

By the President's direction, Lieutenant-Colonel J. W. Barlow has been designated as special disbursing officer, 
and the Department's letter to him of the 6th instant, in so far as it relates to the expenditures on behalf of the 
Mexican Boniulary Survey, is made a part of these general instructious. 
I am, gentlemen, your obedient servant, 

.Iames 0. Blaine. 

* Department ok Fomento, Columzation, Industry, and Commerce, 

Mexico, Section 1st, No. 1930. 
In consideration of the capacity, patriotism, and other qualifications possessed by you, the President of the 
Republic has been pleased to appoint you ongineer-iii-chief of the commission, which, according to the respective 
treaties, will ])roceed to reestablish the monuments along the dividing line between Mexict> and the United States 
of North America. And I communicate this for your satisfaction and give you a term of two months for the 
presentation of vour credentials. 



Liberty and constitution. 
Mexico, October 14, 1S91. 



To Engineer .Iacohii Blanco. /'; 



M. Fernandez, O. M. 



'Department of Fomento, Colonization, Industry, and Commerce, 

Mexico, Section 1st. 
In consideration of the .lualifications possessed by you, the President of the Republic has been pleased to 
appoint you adjunct aBtronomer of the commission to reestablish the monuments along the dividing line between 
Mexico and the United States of North America. And I communicate this for your information and give you a term 
of two months for the presentation of your credentials. 
Liberty and constitution. 
Mexico, October 19, 1S91. 

M. Fernandez, O. M. 
To Engineer Felipe Valle, Present. 

'Depaistment ok Formento, Colonization, Indistrv, and Commerce, 

Mexico, Section 1st. 
In consideration of the qualifications possessed by you, the President of the Republic has been pleased to 
appoint you adjunct astronomer of the connnission to reestablish the monuments along the dividing line between 
Mexico and the United States of North America. And I communicate this for your information and give you a term 
of two months for the presentation of your credentials. 
Liberty and constitution. 
Mexico, October 19, 1891. 

M. Fernadez, O. M. 
To Engineer . I OSE Tamborrel, Present. 

* Translations furnished by Senor Jacobo Blanco, Mexican Commission. 



16 UNITED STATES AND MEXICAN BOUNDAKY. 

SePiores Valle aud Tamborrel subsequently withdrew, their places beiug flnally lilled by the 
appointment of Senores Valentin Gama and Guillenno B. y Puga, with similar commissions. 

The instructions received from the Department of Fomento by the engineer in chief of the 
Mexican section, under date of November 3, 1891, were as follows: 

'To fulfill the leiiulromeiits of the commissions conferred upon you and tlie other enginours who have bcLii 
placed under your orders to reestablish the monuments ou the boundary line between Mexico aud the United States 
of North America, you will observe the following instructions: 

1. On your arrival at Paso del Norte you will, as soon as possible, put yourself iu communication with the 
engineer-in-chief of the boundary commission of the United States, in order to form the International Boundary 
Commission, according to Article II of tlie treaty of July 29, 1882, installing it with the formalities that will be 
agreed upon, and having the corresponding act signed by the chiefs of both commissions, as well as by the adjunct 
astronomers. 

2. You will observe exactly the clauses of that treaty in everything that relates to the fullillment of the 



3. According to Article V of said treaty, yon will determine by common agreement with the engineer in chief 
of the commission of the United States the scientific methods that must be adopte.l for the resetting of the old 
monuments and the erection of new ones, and you will report immediately to the Government the plan of oiieratious 
upon which you shall have agreed. 

4. You will also arrange with the engineer in chief of the United States commission the epochs at which the 
reports referred to iu Article V of the treaty shall be reuilered. 

5. As soon as the plan of operations is settled yon will proceed with the work with all possible activity, giving 
for that object precise and written instructions to each one of the engineers that form your commission. 

6. All the data will be precisely recorded in field note books which will be delivered by each engineer to you 
as soon as they are filled up or the work is finished, with a duplicate copy, botli signed by tho^amo engineer. 

7. In the instructions that you will give to every engineer, the form will be prescribi'd in which they will deliver 
their final results, not only for the general report referred to in Article V, but also with the object of proceeding 
without any delay to the publication of that report. 

8. You will have corrected in the actual maps any error that may be found in the topograi)hlcal coiifigurati(m 
of the ground, .and the new settlements that now exist upon the line or its vicinity will be accurately delineated. 

'J. Besides the reports referred to in the fourth of these iustruotious, you will communicate to the Government 
any matter that may occur in the course of oi)erations of sufficient importance to require consultation. 

Ill compliance with their instructions, the of3Bcers above api)oiiited assembled at I'aso del 
Norte on the 17tli of November, 1801, when a joint meeting was held iu tlie custom house of that 
city, on which occasion the Interuatioiiiil Boundary Commission was duly organized as retjuired 
by the convention. 

Tlie following declaration was drawn u]), copies of which, in English and Spanish, were 
transmitted to the proper authorities at Washington aud the City of Mexico: 

In the piiucipal hall of tlie custom-house of Ciudail Juarez 1,1'aso del Norte) of the Mexican Republic the 
undersigned, engineers in chief and associates of the two sections named for the reestablishmeut of the bonnd.ary 
line between Mexico Jiud the Uuit(^d States of North America, met on the 17th day of November, lyjl, in virtue of 
the treaty concluded in Washington on the 2tlth day of .July, 1882 (and renewed on the 18th day of February, 1889), 
and declared that from the date of meeting the "International Boundary Commission" was organized, for the 
jiurposes of the aforesaid convention, as expressed in Article II of the same. 

In testimony of which we have signed the present document in both the Spanish and English languages, iu 
duplicate. 

J. W. IUhi.ow, 
Lieut. Col., Corps of Evijineim. 
Jacouo Blanco, 
luijo. in ./<•/« de la Com. Mex., Uiihrivu. 
A. T. MOSMAN, 
AsstKlaiit, I'. S. Coast and Cvodctic SuriHiy. 
Kelii'e Vallk, 
Aslo. Adjo. de la Com. Mex. 

JOSIO TAiMliOURKI., 

Jdjunto Aalronomo C. M. de L. 
D. D. Gaillabi), 
First Lieut., Corps of Engineers. 

' Translations furnished by Seilor Jacobo Blanco, Mexican Commission. 



UNITED STATES AND MEXICAN BOUNDARY. 17 

(SKCTIOX <!. 

A plan of operations, as lequirecl by the couveutiou, was then prepared by the engineers in 
chief, with the assistance of the other members, and a copy as follows was submitted, in both 
languages, to each Government: 

Plau of operations, im-luiling uecessary surveys, adopted by the engineers in rhiofof the American and Mexiean 
sections of the International Boundary Commission appointed by their respect ivi> Govevnnients to relocate the old 
monuments and erect new ones .along the frontier line west of the Rio Grande, pursuant to Article V of the treaty of 
July 29, 1882, revived by that of February 18, 1889. 

I. All monuments whose position, after verification, are found to be as located by the International Boundary 
Conmiission of 1849-1856 shall be accepted as positive bouudary marks. They may, however, be repaired or rebuilt 

II. Special astronomical determinations for latitude and longitude at the Ibllowing points will bo made: 
(«) The Initial monument near El Paso; 

(6) The intersection of the one hundred and eleventh meridian with the parallel of 31'' 2p' near Nogales; 
(c) The terminal points, near San Diego and Yuma, respectively, of the azimuth line from the Pacific Ocean to 
the Colorado River. 

III. The position of the bouudary along the parallels of 31" 20' aud SI'' 47' will bo verified by astronomical or 
geodetic determinations for latitude at certain points, which, with those established as above described, will fix the 
direction of these lines. The distances between such definite points may be about 20 miles. 

The points of intersection of these parallels with the meridian section of the boundary may be verified, if 
deemed necessary, by astronomical determinations with the aid of the telegraph, if practicable. 

IV. The moiniments whose positions have been verifieil as above stated, and the new astronomical stations 
located as expressed in paragrapli three, shall form the general line of the bonn<lary l)etween the Rio Grande and 
the one hundred and eleventh meridian. 

V. The lines joining these several points on the parallels shall be run by the method known as "tangents and 
otisets;'' the measurements on the ground along the tangents and offsets to be made as maybe most convenient 
with tape, chain, or stadia, but in case the.se methods are imi^racticable, by triangulation. 

VI. The two azimuth sections of the boundary between the one hundred and eleventh meridian and the Pacific 
Ocean were originally run as straight lines on the surface of the earth, aud should be relocated as such; the same 
principles in regard to existing monuments and new stations to be observed as in locating the parallels. 

VII. Capt. Thos. W. Symous's recommendations regarding the number and location of new monuments will be 
followed in general, subject to such modifications as the joint ( ommission may find desirable. 

VIII. In addition to the astronomical and geodetic work provided for, each section of the boundary survey 
party will make a map of thi- adjoining couutry on its own side for a distance of 24 miles. The topography thus 
obtained should be supplemented by sketches and photographs, especially in the vicinity of the monuments, for the 
purpose of more*xactly defiuiug their positions. 

IX. The western terminal of the azimuth line, from the oue hundred and eleventh meridian to the Colorado, 
will be verified by astronomical or geodetic determinations from Monument No. VI, near Yuma. 

X. The work will be commenced at El Paso and carried on to completio"iTTii the order deemed most advantageous 
by the engineers in chief. 

In testimony whereof we have hereunto signed our respective names in Ciudad .luarez (Paso del Norte) this the 
21st day of November, 1891. 

J. W. Barlow, 
Lieut. Col. Corps of Engineers, U. .S. A. 
Jacobo Blanco, 
Ingo. en Jcfe de la C. M. 

It was found expedient, while the surveys were in progress, to depart from the jilaii of 
operations in the following particulars: 

First. It was agreed at the joint meeting of August 10, 1892, to locate all new monuments on 
the geodetic arcs Joining existing monuments for parallel 31° 47' and the meridian section, 
omitting the results of any astronomical determinations for latitude on these lines. 

Second. A similar agreement was made by the joint commission May 15, 1893, with respect to 
the location of new monuments on parallel 31'= 20'. 

Third. In con.sequence of the above agreements the results of astronomical determinations for 
latitude, taken at points between authentic monuments, were not used in locating the boundary, 
but were used in the later comi)utations for the projection of the maps. 

Fourth. No astronomical determinations for latitude were made along the azimuth lines of the 
boundary except at their extremities. 

As fully explained in section 10 of this report, certain errors occurred in the original survey 
(1840-1850), unavoidable under the conditions existing at that time, and due chietly to inaccurate 
determinations for longitude. 
S. Doc, 247 2 



18 UNITED STATES AND MEXICAN BOUNDARY. 

The present coiuiuissiou, by means of the telegraphic method for longitude and a careful 
measurement of the entire line, was able to determine the amount of these errors and the conse- 
quent loss or gain by each Govenimeiit of certain areas of land. The loss fell most heavily upon 
Mexico, but the present commission, under the treaties, had no power to make any alterations iu 
the boundary. 

In compliance with Article VII of the convention of 1882, an agreement between the engi- 
neers in chief, accompanied by a drawing, was made March 1, 1892, iu regard to the design and 
cost of the monuments. Following is a copy of said agreement: 

The following agreement was entered into this Ist day of March, 1892, between the engineers in chief of the 
International Boundary Commission, respecting the design and inscription for the new monuments to be creeled ou 
the boundary west of the Rio Grande: 

The monuments shall be cast either of steel or iron, as may be found most desirable ; 

The height 6 feet and thickness of metal 2 centimeters, as provided iu the treaty; 

The size at the base to be 12 inches square, and at top 9 inches sciuare; 

The pyramid at top to have a base 9 inches square and 6 inches in height ; 

The base of the monument will have a flange 4 centimeters in thickness, where it joins the sides, diminishing 
to 2 centimeters at the outer edge, and will be 6 inches wide; through this flange on each side will be a hole 1 inch 
iu diameter; these holes are to receive the fastening bolts to secure the monument in place; 

The mouumeut will be filled either with concrete or sand well packed, as may be found most practicable, and 
to be fastened iu place by four 1-inch bolts well secured to the natural rock foundation, where jjossible. AVhereno 
rock foundation is available a foundation of concrete, 3 feet square and 2 feet deep, will be prepared of Portland 
cement and sand in proportion of about one to tliree. In these cases the fastening bolts will extend through the 
foundation, and be secured below by suitable heads and washers; the upper ends of these bolts will be provided 
with a thread and nut, the latter round and ])ut ou with pipe tongs; 

t>n the west side of each monument may be attached two socket rings for holding a flagstaff, for the purpose 
of more easily verifying the line between monuments remote from each other; these rings will be placed, one at the 
top of shaft, the other 12 inches below, and will be carefully located iu the plane of the boundary ; 

The engineers in chief further agreed that the inscriptions to be placed on the new monuments should be as 
follows: 

Ou north side : " Boundary of the United States, treaty of 1853, reestablished by treaties of 1882-1889." 

On south side: " Limite dc la Republica Mexicaua, tratado de 1853, restablecido por tratados de 1882-1889." 

It is at the present time impossible to prepare au accurate estimate of the cost of the monuments, including 
their conveyance and setting up, as required by Article VII of the treaty of 1882. An approximate estimate, however, 
can be given, based upon known difficulties attending the transportation of men and material in a desert country. 

The weight of the monuments as designed is 710 pounds, which is 200 j)ounds greater than the weight suggested 
in the treaty. If made to weigh 500 pounds, with <i height of 6 feet, of 2 centimeters thickness of metal, the monu- 
ment would be more sh'ndir than the design now recommended; it would bo a less conspicuous maii: and, therefore, 
not deemed as desirable. Smaller dimensions than those given would seem inappropriate. 

It is proposed to have as many of the monuments cast whole as can be transported to their locations ou wagons, 
but for locations inaccessible for wagons the monuments will be cast in sections, for transportation ou pack mules. 
These sections will be four side jilates, two of which are 5 feet long, 12 inches wide at base, 9^ inches at top; two 
lOJ inches at base, 8 inches at top ; the base plate 24 inches square ; and top section, which will comprise the pyramid 
and 12 inches of the shaft. The weight of these pieces will be as follows : 

Pounds. 

2 side plates, 135 ponnds each 270 

2 side plates, 110 pounds each 220 

lb:i8e plate, 110 pounds 110 

1 top section, 110 jiounds , 110 

Total 710 

E.stimate of cost of monuments, including concrete bases, transportation, and setting in ])lace: 

Castings, 710 pounds, at 4 cents $28.40 

Wrought bolts and uuts, 80 pounds, at 5 cents 4. 30 

Concrete, 18 cubic feet 15. 00 

Sockets for flagstaff 1.00 

Transportation by wagon 15. 00 

Transportation by pack mules 10. 00 

Settiug iu place 15.00 

Contingencies 11. 30 

Total for each monument 100. 00 

This is considered a fair probable average cost. In some instances transportation will greatly exceed the 
estimate, and in others it is hoped there will be a proportionate reduction. 

J. W. Baklow, 

Lieut. Col., Corps of Engineers, U. S. A., Engineer in Chief, American Section. 

.lACOBO Blanco, 
lingineer in Chief, Mexican Section, 




Type of New Montmext, showixg Base. Modelo he rx Moxumexto Nuevo, Mostkaxdo la Base. 



UNITED STATES AND MEXICAN BOUNDARY. 19 

SUPPLEMENTARY AGREEMENT UPON THE SAME SUBJECT. 

The f'ollowiug additional agreement was entered into tliis 9tli day of March, 1892, between the 
engineers in chief of the American and Mexican sections of the Boundary Commission : 

I. All mouuments, old and new, will be numbered consecutively, beginning at the initial monument near El 
Paso. The letters "NO" will be cast in the metal on the east side of each new monument, and proper figures 
afterwards attached by screws, bolts, or rivets. 

II. It being understood that the new monuments would bo procured in the United States, the estimates of 
cost— approximately $100 per monument— were based on the currency of that country. 

III. When old monuments are retained the original inscriptions will be preserved, if possible, but when repairs 
are made the following inscription -will be added : 

On north side: "Repaired by the Boundary Commission created by treaties of 1882-1889." 
On south side: "Eenovado por la comisiou de limites creada por los tratados de 1882-1889." 

IV. The better to preserve the monuments from injury by trespassers or animals, it is agreed that near cities 
the nionnments shall bo inclosed by an iron picket fence 4 feet high, and inclosing a space 4 feet wide on each side of 
the monument. In other localities barbed wire, surrounding the mouuments at a distance of 2 feet, supjiorted on 
wrought-iron posts attached to the foundation, will be sufficient protection. 

V. It is estimated that the average cost per monument for the protection above mentioned will be about $10, 
United States currency. 

J. W. Barlow, 
I.ieiil. Col., Corps of Jinyhieira, V. S. A., Kuijiueer in Chief, American Section. 

.Iacobo Blanco, 
Euijinier in Chief, Mexican Section. 

During the i)rogress of operations it was found expedient to deviate in some minor ijarticulars 
from the above agreements. By verbal understandings between the engineers in chief the follow- 
ing deviations were adopted : 

First. The estimated cost was considerably exceeded, owing to the exigencies nf transportation, and reached an 
average of $150 per monument. 

Second. It was considered inexpedient to inclose all the monuments witli fences, and but three were thus 
finally protected. 

Third. The provision for filling the mimuments with concrete or sand was not found U> be desirable, after a few 
trials, and was discontinued. 

Fourth. The weight of the castings exceeded the estimate, reaching an average of 800 pounds per monument. 

Fifth. The letters "NO," in connection with the figures ou the monuments, were considered unnecessary and 
were omitted. 

Sixth. Beneath the inscriptions on the north and south sides, respectively, of each monument, was added the 
following penalty notice in English and Spanish: "The destruction or displacement of this monument is a misde- 
meanor, punishable by the United States or Mexico ; " " La destruccion o dislocacion de estc monumeuto es un delito 
puulble por Mexico o los Estados Unidos." 

Seventh. After a number of sectional monuments had been put up, the design was changed to meet the difficul- 
ties of pack transportation. The new design provided 7 pieces— a base, a cap, and 5 intermediate sections, the latter 
each 14 inches high, resting one above another, and all held in place by a vertical bolt connecting the base and top 
section, the cap being fastened with rivets. 

The sectional monuments, when erected, were of the same appearanc^e as those cast solid. 

Agreement between the engineers in chief with respect to the destruction of Monument No. 
255 and the adoption of a new site : 

San Diego, Cal., April 1, 1S95. 

Monument No. 255, built of granite, near Tijuana, having been destroyed by the fiood of .January, 1895, the 
two engineers in chief made a careful examination of the locality, but were unable to discover any parts of the lost 
monument. It had evidently been buried many feet below the bed of the river, which had so changed its course as 
to flow over the original site. It being deemed inexpedient to attempt to erect another monument ou the old site, 
it was agreed to abandon that location and adopt a new position for this monument on permanent ground. Accord- 
ingly, a survey was made in March, 1895, under the personal supervision and through the cooperation of the 
engineers in chief, and a site selected 1,080.()2 meters to the eastward of the old location upon which to erect a 
duplicate of the lost monument. 

.1. W. Barlow, 
Lieut. Cot. Eiuira., V. S. A., Engineer in Cliief American Section. 
Jacobo Blanco, 
Im/o. en Jefe de la Com, Mex. 

A granite monument, a duplicate of the one destroyed, including a protecting fence, was 
erected at the point determined, and the map and records changed to conform to the new location. 



20 UNITED STATES AND MEXICAN BOUNDARY. 

SECTION 7. 
JOURNAL OF PROCEEDINGS OF JOINT COMMISSION. 

El Paso, Tex., August 19, 1893. 
The joint commission met at 9.30 a. m. Present, Seuor Jacobo iJlaiico, Col. J. W. Barlow, 
Sefior Felipe Valle, and Lieut. D. 1). Gaillard. (Mr. Mosmau absent in camp at San Bernardino.) 
The measured distances along parallel 31° 47' and the meridian section of the bonndaiy were 
compared and found to agree closely. 

The tangents and meridian, as traced by each section, and the offsets to existing monuments 
were then compared and found to agree well. 

It was agreed to accept all existing monuments on this portion of the boundary, and to locate 
all new monuments on the geodetic arcs joining existing monuments for the particular part of the 
boundary considered in the meeting to-day. (Parallel 31° 47' and the meridiau section.) 

Jacobo Blanco, 
Emjineer in Chkf Mexican Section. 
J. W. Barlow, 
Engineer in Chief American Section. 
Felipe Valle, 
Adjnnto Astronomo dc la Seccidn Mexicana. 
D. D. Gaillard, 
First Lieut, of Engineers, U. S. A. 

Yuma, Ariz., 3Iay 15, 1893. 
The joint commission met at 10 a. m. 

Present, SeFior Jacobo Blanco, Col. J. W. Barlow, Mr. A. T. Mosman, SeFior Valentin Gama, 
and Lient. D. D. Gaillard. (Seuor Felipe Valle absent in the City of Mexico.) 

The measured distances along parallel 31° 20' were compared and found to agree well with 
each other and with the astronomical determination of the total distance. 

It was agreed to accept all existing monuments on this parallel except the one on the west 
side of the Pedregosa Mountains, which is to be further inspected by Col. J. W. Barlow and 
Seuor Jacobo Blanco, and by them accepted or rejected. 

It was agreed to hicate all new monuments for parallel 31° 20' on the geodetic arcs joining 
existing accepted monuments. 

Jacobo Blanco, 
Ingo. Jefe fie la Com. Mex. 
J. W. Barlow, 
Lieut. Col., Corps of Engineers. 
A. T. Mosman, 
Assistant, U. S. Coast and Geodetic Survey. 
Valentin Gama, 
Asto. Adjo. de la Com. Mcx. 
D. D. Gaillard, 
First Lieut., Corps of Engineers. 

Camp on Parallel 31° 20' West of the Pedregosa Mountains, 

Jul}/ 3ii, 1893. 
Pursuant to an agreement made by the joint commission of the United States and Mexican 
boundary at Yuma, Ariz., on the loth day of May last, the engineers in chief of the two sections of 
the commission, viz, Seilor Jacobo Blanco and Lieut. Col. J. W. Barlow, have on this day carefully 
inspected the monument at the point mentioned, and decided to accept it as one of the original 
monuments of the boundary. 

Jacobo Blanco, 
Ingo. en Jefe de la Seccion Mexicana. 
J. W. Barlow, 
Engineer i7i Chief of the American Section, 



UNITED STATES AND MEXICAN BOUNDARY. 21 

San Diego, Cal., December 28, ISDi. 
It is hereby agreed between the engineers in chief of the United States and Mexican Boundary 
Comraission that the monument referred to in agreement dated May 15, 1893, and its supplement 
of July 2C, 1893, is understood to be the monument near the Gallardo Mountain which was found 
and located by the American surveying party. 

Jacobo Blanco, 
Iiigo. en Jefe Seecioii Mexicana. 
J. W. Barlow, 
Lieut. Col. Engrs., U, S. A., Engineer in Chief American Section. 



In the village of Nogales, State of Sonera, on the 15th day of November, 1893, there were 
present Mr. B. A. Wood, of the American section, and Capt. Gaspar Martinez Oeballos, of the 
Mexican section, of the International Boundary Commission, who compared, in the presence of 
Senor Jacobo Blanco, engineer in chief of the Mexican section, the data and results obtained, by 
both sections, along the azimuth line, from the ertremity of parallel 31° 20' to the Colorado Kiver, 
as far as Monument IX. 

The comparison of said data and results showed clearly that the monuments as far as No. IX 
were well identified, with the exception of No. XIX. No. XI was not found. 

It was agreed, consequently, to accept the monuments from the extremity of the parallel to 
No. IX, inclusive, with aforesaid exceptions, and interpolate between them the new monuments in 
a straight line, admitting, in case of discrepancy, a difference not exceeding 2 meters, which will 
be equally divided, it being understood, however, that should the ditterence be considerable, 
though within the limit, the line shall be checked and the discrepancy be reduced as much as 
possible. 

B. A. Wood, 

Assistant Engineer, American Section. 
Caspar Martinez Ceballos, 

Ca2h 2, Ingo. Ayudte. de la Seccion Me.r. ' 
Jacobo Blanco, 

Ingo. en Jefc <l cJa Seccion Me.r. 

Yuma, Ariz., December 14, 1893. 
A joint meeting of the International Boundary Commission was held in the ofiQce of Senor 
Jacobo Blanco, engineer in chief of the Mexican section, at Yuma, at 9 a. m. to day. 

Present: Senor Jacobo Blanco, engineer in chief of the Mexican section; Mr. A. T. Mosman, 
assistant. United States Coast and Geodetic Survey, and Lieut. D. D. Gaillard, United States 
Corps of Engineers. Absent: Col. J. W. Barlow, United States Corps of Engineers, suflering 
from a broken arm ; Senor Valentin Gama, absent in the field, and Don Francisco Diaz Eivero, 
recently appointed, en route from the City of Mexico. 
It was agreed : 

First. That the astronomical length of parallel 31° 47', the meridian section, and parallel 31° 
20', as determined by the United States section,* will be accepted as the standard of length for 
this portion of the boundary. 

Second. In deciding the measured distances between monuments on this i)artof the boundary 
equal weight will be given to the United States and Mexican results and a mean of these taken. 
These means shall then be adjusted to conform to the astronomical lengths of the portions 
considered. 

Jacobo Blanco, 
Engineer in Chief, Me.tican Section. 
A. T. Mosman, 
Assistant, Const and Geodetic Survey. 
D. 1). Gaillard, 
First Lieut, of Engineers, TJ. S. A. 

*NoTE. — The Mexican scctiou ilid not observe for loiigitiule at tLc western extremity of tlie line ou parallel 
31^47'. 



22 UNITED STATES AND MEXICAN BOUNDAKY. 

A meeting ol' the International Boundary Commission was held at Yuma, Ariz., on March 
20, 1894, in the ottice oF Senor Jacobo Blanco, engineer in chief of the Mexican section of the 
commission, at 9 o'clock a. m. 

Present: Senor Jacobo Blanco, engineer in chief of the Mexican section; Mr. A. T, Mosman, 
assistant. Coast and Geodetic Survey, and Lieut. D. D. Gaillard, Corps of Engineers, United States 
Army. Absent: Col. J. W. Barlow, United States Corps of Engineers, at Washington, D. C, and 
Senor Valentin Gama, in the field. There were also present at this meeting Capt. G. Martinez 
Ceballos, of the Estado Mayor Especial of the Mexican Army, assistant engineer of the Mexican 
section of the International Boundary Commission, and Mr. E. L. Ingram, assistant engineer of 
the American section. 

The direction and distances along the boundary line between the Colorado River and IMonu- 
ment IV were compared and found to agree closely, and it was agreed to accept Monuments VI, 
V, and IV as authentic. 

Jacobo Blanco, 
Engineer in Chief of the Mexican Hection. 
A. T. MosMAN, 
Assistant, U. S. Coast and Oeodetic Survey. 

D. D. Gaillard, 

First Lieut., Corps of Engineers. 

E. L. Ingram, 

Assistant Engineer of American Section. 
Gaspar Martinez Ceballos, 
Capitain de E. M. E., Ingeniero Ayudante de la Sec. Mex. 



San Diego, Cal. 

On the 19th day of June, 1894, in the office of the American section of the International 
Boundary Commission. Present: Col. J. W. Barlow, Mr. A. T. Mosman, and Lieut. D. D. Gaillard, 
United States Commissioners; Seiior Jacobo Blanco, engineer in chief of the Mexican section of 
the aforesaid International Commission, and Senor Valentin Gama, engineer and assistant 
astronomer of the same. Was discussed — 

The actual condition of the work of the two sections, which was summed up as follows: 

1. The tracing of the lines from the Rio Grande to the Pacific is finished, with agreement 
between the two .sections. 

2. In general the distances along these lines have been measured or determined, with the 
exception of some partial remeasurements, which perhaps it may be necessary to make and which 
do not affect in any practical manner at present the international boundary already established. 

3. The replacing of old monuments and the interpolation of other new ones has proceeded 
up to monument 248, and will be entirely concluded from the Rio Grande to the I'aciflc in July. 

4. The topographical fieldwork in the agreed zone of 2i miles on each side of the line is 
finished on the part of the American section in their territory, and the field maps of their whole 
work will be finished before the expiration of the present convention (October 12, 1894), but the 
final maps to accompany the report can not be made till the Mexican section has finished their 
topography and made their field maps of the same. 

The ^Mexican section, due to its smaller resources and force, principally during the first part 
of the work, lacks still the topography along the two azimuth lines. In that of Sonora the work 
is now actually progressing with all activity, and another topographical section will be organized 
in that of California about the end of July. 

For what each section respectively lacks for camp and office work and for the common work ot 
both ou maps and detailed reports an extension for two years, reckoned from the expiration of the 
time granted by the convention of October, 1889, is considered necessary, and such an extension 
is respectfully requested from each one of the two Governments by the respective sections of the 



UNITED STATES AND MEXICAN BOUNDARY. 23 

International Commission, with the understanding that the work will be prosecuted with all 
activity in order to finish, if possible, before the limit requested. 

J. W. Baelow, Jacobo Blanco, 

Lieut. Col. of Engineers. Engineer in (jhief of the Mexican Section. 

A. T. MosMAN, Valentin Gama, 

A.^.si><tanf, Coast and Geodetic Surrey. Engineer and Assistant Astronomer. 

D. D. Gaillakd, 
First Lieut, of Engineers. 

San DieCtO, Gal., October 1, 1894. 
At a meeting of the Joint commission, held at the residence of Ool. J. W. Barlow, at 3 p. m., 
at which were present all of the members, it was unanimously agreed that, subject to the approval 
of the proper departments of our respective Governments, the commission hereby adjourns, to 
meet next on October 11, 1805, at Washington, D. C, there to adopt a plan of work for the 
completion of the final maps of the boundary line and to prepare the i-eport. 

.T. W. Barlotv, .Jacobo Blanco, 

Lieut. Col. of Engineers, U. S. A. Engineer in Chief, Mexican Section. 

D. D. Gaillard, Valentin Gama, 

First Lieut, of Engineers, U. S. A. Assistant Astronomer. 

A. T. MosMAN, 
Assistant, U. S. Coast (uid (liodrtic Surrey. 



SECTTOX S. 
ASTRONOMICAL DETERMINATIONS. 

The original plan agreed on by the Joint commission for running the boundary was to deter- 
mine both the latitude and longitude of the extremities and turning points of the boundary, at 
or near which points the monuments erected by the original commission were reported as still 
standing, and to observe for latitude and azimuth on the jjarallels at points about 20 miles apart. 

Longitude. — The method used for longitude by the United States section was exchange of 
signals by telegraph. Usually ten nights' exchanges were obtained, five with one observer at 
eastern station and the other at western, then five more with the positions of the observers 
reversed. The same stars were observed at both stations for time and instrumental corrections 
to eliminate errors in the right ascensions of the stars used. 

The method used by the Mexican section was to refer the points of observation (stations) to 
the meridians of Tacubaya and Mexico by exchange of telegraphic signals. The corrections and 
rates of chronometers employed were obtained by observations of meridian transits registered by 
the ear in Ciudad Juarez, and with chronograph at Nogales and Yuma. 

The longitude of Monument 1, where the parallel of 31° 47' leaves the Eio Grande, was fixed 
by a triangnlation by the United States section, connecting the monument with the longitude 
station at El Paso, and by signals by the Mexican section to the longitude station at Juarez. The 
longitude of Monument 40, at the intersection of parallel 31° 47' with meridian, was obtained 
directly by the United States section using a temporary fiehl telegraph line, erected by direction 
of General Greeley, Chief Signal Officer, United States Army, connecting with the Western 
Union telegraph line at Separ, on the Southern Pacific Railway. General Greeley also furnished 
operators at both ends. 

The longitude of Nogales was transferred to Monument 127, at the intersection of parallel 
31° 20' with the one hundred and eleventh meridian, as determined by the original commission, 
by a triaugulation by United States section connecting the monument with the longitude station 
at Xogales. This triangnlation was repeated by the Mexican section. The longitude of Monu- 
ment 204, 20 miles below Yuma, on the line connecting Monument 127 with the initial point in the 
Colorado, was obtained from the observed longitude at Yuma by triangulatiou by the United 



24 



UNITED STATES AND MEXICAN BOUNDARY. 



States section, repeated by the Mexican section. The longitude of Monuiiieut 207, wliere the line 
from the junction of the Gila and Colorado leaves the river, was obtained trom the same triangu- 
lation. The longitude of Monument 258, on the Pacific, was furnished by the Coast and Geodetic 
Survey based on o'.iservatious for longitude made at San Diego in 1892, connecting this point with 
the main chain of longitude stations on the Pacific coast and reduced to the monument by Coast 
and Geodetic Survey triangulation. 

The details of these triangulations will be found in another part of this report, under section 
No. 9. 

Latitudes. — It was arranged by the Joint commission that the parallel of 31° 47' should be 
determined by occupation of alternate stations by the United States and Mexican astronomers 
along the i)arallel, about 20 miles apart, for latitude and azimuth. 

In pursuance of this plan, observations were made by the astronomers of both sections at 
Monument No. 1, on the Rio (Trande, and at Monument Xo. 40, at the western extremity of 
this parallel. The United States section occupied two intermediate stations and the Mexican 
section two. 

Along the parallel of 31° 20' a different jilan was adopted. Along this parallel each section 
of the commission observed independently of the other. Both sections observed at the eastern 
end, and at Nogales near the western end; the Americans at six intermediate stations and the 
Mexicans at four. The stations were not identical, as the Mexican section observed only at 
monuments, and as these monuments were very unequally distributed as to distance, in some 
places being over 40 miles apart, the United States section had two stations where no old 
monuments existed, so as to divide the line as nearly as possible into sections of 20 miles each. 
By a vote of the joint commission no account was taken of the resulting latitudes at stations 
between old monuments in fixing the final line. Observations were also made at Yuma and at 
Monument No. 204, 20 miles below Yuma, on the Colorado River, and at Monument No. 258, on 
the Pacific. 

Azimuths. — At each latitude station observations for azimuth were made by the United 
States section, usually on three niglits, on Polaris near elongation, and the direction of the new 
tangent started from each azimuth station, fixed by repeated measures of the angle between the 
azimuth mark and the most distant point of the tangent visible from the station. 

The azimuth of the old tangent ending at the station was checked in the same manner. 

The method used by the Mexican section was to measure the angle between Polaris and a 
mark two or three times in both positions of the instrument; the group formed in this way is 
called a series in the following table. 

The azimuth of each tangent was corroborated at its extremity by the observation of the 
back azimuth, 

Loiiyitiicle results hi/ United States section. 
DIFFERENCE OF LONGITUDE BY TELEGRAPH. 



[Observers, C. H. Sinclair and G. K 


Putnam.] 






stations. 


Number 
Bights. 


longitude. 


Probable 




= 


To a'iu 

14 43.690 
17 48.520 
6 52.626 


ioioos 

±0.007 
± 0. 009 
±0.013 


Yuma, Ariz. Nogales Ariz 




Corner near Monument No 40-El Paso Ttx 





LONGITUDES FROM GREENWICH. 



Station. 


Time. 


Longitude. 




h. m. s. 
7 05 57.350 
7 12 49.976 
7 23 45.870 
7 38 29.564 
7 48 38.074 


100 29 20.25 
108 12 29.64 
110 56 28.05 
114 37 23.40 
117 09 40.11 


Boundary corner 


Nogales 




San Diego 





UNITED STATES AND MEXICAN BOUNDARY. 

Longilude rtsults bij United States section — Continueil. 
LONlilTUDE OI" TROMIKEXT POINTS OM BOUNDAKT. 



Points. 



Conrthonae, El Paso 106 28 55.U 

Cathedml, Juarez. Mexico 100 29 4.72 

Federal building, El Paso 106 29 9.58 

Monument No. 1, Rio Grande | 100 31 39.03 

Monument No. 40, upper corner ' 108 12' 29.67 

Monument No. 53, lower corner ' 108 12 29.67 

Monument No. 122, Nog.-xles ! 110 50 34.53 

Monument No. 127, corner ! Ill 4 34.45 

Monument No. 204, east bank Colorado 114 40 48.64 

Monument No. 207, west bank Colorado 114 43 54.31 

Monument No. 258, Pacific 117 7 31.89 



25 



UNITED STATES LATITUDE OBSERVATIONS. 

All the latitude observations were made with the Wiirdemann zenith telescope No. 20. The 
principal dimensions of this instrnment are: Clear diameter of objective, 07 mm. ; focal lengtli, 82G 
mm. ; diameter of vertical circle, 144 mm. The eye]>iece uiagniries about 70 diameters. The vertical 
circle is graduated to fifteen minute spaces, and its vernier reads to half minutes. The latitude 
level carries a 2 mm.gradnation of 70 divisions, numbered contiuiioiislyfroiii one end to the other. 

The time was computed from sextant observations of the sun's altitude. 

The instrument was usually mounted on a wooden pier, similar to that used for the azininth 
instrument, but larger and heavier, and covered by a portable tent. At Nogales and at Yuma tlic 
zenith telescope was mounted upon the brick pier which had previously been used as a latitude 
pier by the Coast and Geodetic Survey longitude party. 

The mean places -of the stars observed for latitude were furnished in advance by Prof. T. IT. 
Safford, of Williams College, Williamstown, Mass. (See catalogue in report of United States 
section.) 

The value of micrometer was determined at every station except at No. 14 by transits across 
the thread of polaris near elongation, the thread being set at each half turn in succession for 
the twenty turns near the middle of the field of the telescope, and the time of transit observed by 
eye and ear. 

The following table gives the results for latitude by the United States section : 

Latitude results of Vnited States section. 



No. of United 
states station. 


ment. 


Number 
ofnigbts. 


Instrument used. 


Number 
of obser- 


Results for lati- 
tude. 


Probable 
error. 


Observer. 




15 
26 
40 


* 


Zenith telescope.. 


67 
39 
40 
130 
99 
102 
99 
100 
101 
106 
126 
121 
105 
25 
96 


31 46 59.40 
60.34 
58.08 
59.72 

31 19 61.79 

57.94 
56.86 
58.99 
66.07 
64.67 
57.58 
60.73 

32 43 34.69 
32 29 .91 
32 32 1.34 


±0.00 
± .07 
± .05 
± .04 
± .04 
± .04 
J- .04 
± .03 
J- .03 
± .04 
i .03 
± .04 
± .03 
± .08 
± .04 


J. F. Hayford. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 


















do 




67 
77 


do 

do 






do ■.:■■::■■"■ 




98 




do 




111 4 
12'' 5 






To 






4 














dn 












26 



UNITED STATES AND MEXICAN BOUNDARY. 



UNITED STATES AZIMUTH OBSERVATIONS. 

All the azimuth observatious were made with Fautli repeating' theodolite No. 725. The hori- 
zontal circle, 25 cm. (10 inches) in diameter, is graduated to 5' spaces, and is read by two opposite 
verniers to 5", It is furnislied, on the horizontal motions, with axis clamps and tangent screws 
working against spiral springs. The telescope has a focal length of 41 cm. and an objective 
45 mm. in diameter. The eyepiece used magnifies about 30 diameters, and is furnished with a 
micrometer with which the azimuth observations were made, except at Monument 53, where the 
azinmth was measured on the horizontal circle by repetitions. 

Tlie theodolite was mounted on a wooden pier in the large observatory tent. The pier was a 
hollow, triangular column, built of 3-inch pine, put together with screws and banded at top and 
bottom with heavy hoop iron. The pier was set as a fence post at eacli station, about 45 cm. of its 
length being below ground. The earth was tamped solidly around it, and its hollow interior was 
also lilled with earth to give it greater rigidity. 

Tlie mark used for azimuth work was an ordinary bull's eye lantern showing through a hole 
an inch iu diameter in front of the small box which served to protect it from the wind. This light 
was placed from 1 to 3 miles from the theodolite at each station. The time was obtained with 
sufficient accuracy for the azimuth work by sextant observations of the sun's altitude. 

With the exception of one station all the azimuth observatious were taken with the eyepiece 
micrometer by the method described in Bulletin No. 21, December 12, 1890, of the Coast and 
Geodetic Survey. 

All the observatious were taken near elongation, usually witliin one hour, and polaris was used 
at each station. 

Tlie azimuth light having been previously placed nearly in the vertical plane of the star, the 
observations consisted simply of the measurement with the eyepiece micrometer of the small 
horizontal angle between the star and mark, the chronometer time of each star pointing being 
noted. 

Each set of observations consisted of five pointings on the mark, followed by five on the star, 
with telescope direct; five more pointing on the star, followed by five on the mark with telescope 
reversed, completed tlie set. The level was read at the beginning, middle, and end of each set in 
both xjositions of the telescope. 

Having determined the azimuth of the mark we need uext to determine the exact location of 
a point to the westward (or eastward), on the prime vertical of the station, said point serving with 
the station to fix the direction of the "tangent" to be continued forward to the next station. 

A point was first placed as uearly in azimuth 90° as could be done by a single pointing and 
reading of tlie horizontal circle, usually within ten seconds. The distance to this point from the 
station was measured by chain or stadia, and the angle between the point and the azimuth mark 
was measured with the theodolite used as a repeater, each set of observations consisting of six 
repetitious of the angle and six of the explement (360 angle). The linear correction at right 
angles to the line of sight necessary to place the point in the prime vertical of the station was 
then computed and the final point set by linear measurement from the approximate point. 
Azimttih results J>ij ViiHed States section. 



Locality. 



Monument No. 1... 
Monument No. 15 . . 
Monument No. 26.. 
Monument No. 40.. 
Monument No. 53 . . 

San Luis 

Monument No. 07 . . 
Monument No. 77 . . 
Dutch Cliarley'8... 
Monument No. 98 . . 
Monument No. 111. 
Nog.iles 

Monument No. 204 . 
Monument No. 258 . 



Method used. 


Nnm- 
her of 
sets. 


Micrometer... 




...do 




...do 




...do 




Theodolite.... 




Micrometer... 


13 


.-..do 


12 


....do 


10 


...do 


12 


...do 


27 


...do 




....do 




...do 




....do 




....do 





Kesulta for 
azimuth. 


Prohahle 


Observer. 


178 30 40.11 


±0.21 


J.F.Hayford. 


37.46 


± .25 


Do. 


178 31 47.46 


i .23 


Do. 


1 26 10.16 


± .34 


Do. 


89 57 27.40 


± .70 


1).,. 


1 23 12.93 


± .23 


Do. 


181 27 55.52 


± .14 


Do. 


181 28 31.84 


± .19 


Do. 


181 28 12.96 


± .10 


Do. 


181 27 56.39 


± .14 


Do. 


178 31 29.03 


± .20 


Do. 


178 33 39.19 


± .26 


Do. 


178 32 1.12 


± .14 


Do. 


178 31 21.01 


± .21 


Do. 


181 28 39.30 


± .27 


Do. 



UNITED STATES AND MEXICAN BOUNDARY. 



27 



ASTUONOMICAL RESULTS BY MEXICAN SECTION. 

Longitude. — The ]ioints detennined by the Mexican section were: Juarez, Momuneiit ISIo. 1, 
i^ogales, and Yuma. 

The first and the last two were determined by reference to the meridians of Tacubaya and 
Mexico by exchange of signals by telegraph. The chronometer corrections and rates employed 
were obtained by observations of the transits of stars with a transit instrument, made by 
Troughtou and Sims, of about 30 inches focal length, and registered by eye and ear at Juarez and 
by chronograph at Nogales and Yuma. 

The longitude of Monument No. 1 was obtained from the station at Juarez by exchanges of 
flashes of light. 

The following table gives the results obtained for longitude of the dilferent points from 

Greenwich : 

Table of longitude resnlta hij Mexican section. 



No. of 

astronom- 

ic-ll 


Locality. 


Nuu,ber 
of nights. 


Number 1 
Method. ' of obser- Eesnlta. 
vations. 


Probable 


Observer. 


1.. 


Juarez (cliurcli) .. 
Monument No. 1.. 
No-'ales 


3 
C 
3 


;.. »,i. s. 

Telegraph 12 7 5 55.98 

Lio-ht flashes ' 7 C C. 54 


±0.24 
± .25 
+ .03 


V. Gama. 
F.Valle. 
Do. 
G. B. y Pnga. 




Telegraph 35 7 23 45.G1 















Latitude.^. — Twelve astronomical stations were established at various points on the line for the 
determination of latitude. At four of these— see the following table— an altazimuth of 12 inches 
diameter of limb was used, and difference of zenith distance of pairs of stars selected so as to be 
reduced by the "Talcott method" were observed, except at Monument No. 1, where the latitude 
was determined by circum-meridian zenith distances. At the eight remaining points the latitude 
was determined by the "Talcott method," using a zenith telescope of about ;)0 inches focal length. 

The results given in the following table are reduced to the center of the monument named by 
measurement, except those given for Station No, 7. and Yuma, where the latitudes correspond to 
the points of observation : 

Latitude results iy Mexican section. 



Monument No. : 



Monument No. 21 . 
Monument No. 40 . 
Monument No. 53 . 
Monument "No. 64 . 



Monument No. 98 

Monument No. Ill 

Nogales — Monument No. 

Yuma 

Monument No. U at Ti.i us 



Altazimuth 

...do 

Zenith telescope . 



Altazimuth 

Zenith telescope. 



Altazimuth 

Zenith telescope . 



31 


46 


59.47 


31 


47 


0.87 


31 


46 


58.85 


31 


46 


59.66 


31 


20 


1.83 


31 


20 


2.60 


31 


19 


59.65 


31 


20 


3.02 


31 


19 


58.27 


31 


20 


0.97 


32 


43 


34.22 


32 


32 


25.26 



* This latitude is not exactly that of the astronomical station, but is that of the pile of stones that Sr. Valle mi stock for Monument No. XX. 

Azimuths.— At nine of the latitude stations there were made observations for azimuth also, 
and at seven other points observations for azimuth alone were made, making 16 points at which 
azimuth was observed to be used in tracing the tangents to the parallels and to obtain the azimuth 
of the oblique lines. 

The iustrunieiit usually employed was an altazimuth of 12 inches, except at Monuments Nos. 
204 and 207, where one of 8 inches was used. 



28 



UNITED STATES AND MEXICAN BOUNDARY. 



The nietliort ibllowed was to measure the angle between Polaris and a .signal two or three 
times in both positions of the instrument, the group thus formed being called a series in the 
following table : 

Table of asimuth results by Mexican seetioii. 



Ko. of astro- 1 

noraicalsta- Locality, 
tioii. 1 


Series. 


Nights., Method used. 


Besults for azi- 
muth. 


Probable 
error. 


Observer. 




Moimmcnt No. 1 

Monument No. 2 




3 Altazimuth... 


191 31 31.2 
233 33 23.2 
188 34 50. 1 


iO.13 
+ .42 


F. Valle. 

C. A. Gonzalez. 

F. Vallc. 

C. A. Gonzalez. 

r. Valle. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

D... 
Do. 






MonnmentNo.l5 

Monument No. 21 

Monument No. 40 

Monument No. 53 

Monument No. 64 

Monument No. 83 

Monument No. 98 

Monument No. 111.... 
Monument No. XIX.. 


3 
3 
4 
3 


do ■. 

do 

do 

......do 

.....do 

do 

do 

do 

do 

do 

do 


176 30 45. 5 ± . 59 
269 50 37.8 + .40 
2.7 +.96 
89 59 57. 5 1 + . 90 








90 0. 3 
89 59 28.7 
3 36 18.0 
179 35 59.2 
179 30 31.3 
181 !9 57.6 
109 33 49.5 
179 39.8 
85 4 44.7 


± .50 
± .37 
+ .20 
± .73 
±•.39 
± .46 
+ .51 


7 








Monument No. 204.... 
Monument No. 207.... 
Monument No. 221.... 



The aziiiinths in this tahle arc couiitctl from the south lij^ tho west. 

FINAL ASTRONOMICAL RESULTS. 

Tlie results for longitude as given by the United States section were adopted by the Mexican 
section. The reason for this was that the United States section determined differences of longitudes, 
e.xcbangiug observers to ascertain and eliminate their personal equation, and observed the same 
stars at both stations. The Mexican section determined differences of longitudes with Tacubaya 
without exchange of observers, and dift'erent stars were observed at the two stations. 

The results for latitude are given in the following table. The adopted results are (when both 
sections observed at the same station) the mean, by weight, of the United States and Mexican 
results from their respective observations. 

Finul results for latitude. 



Old No. New No 



Mexican Station 



Station No. 9 . 




31 46 08.08 

31 46 59. 72 

31 19 61.79 

31 19 57.94 



31 19 06.07 

31 19 04.67 

31 19 57.58 

31 19 60.73 

32 29 1.00 
32 43 34.09 



Mexican results. 



31 40 59.47 
31 47 0.87 



31 40 59.40 



,. 


40 


58.85 


- 


■"1 


31 


40 


59.60 


± 


.00 


31 


19 


61.83 


* 


.19 


31 


19 


02.00 


± 


.14 


31 


19 


:: 




.05 


31 


19 


03.02 


± 


.17 


31 


19 


58.27 


i 


.18 


31 


19 


60.97 


* 


.11 


32 


43 


34.22 


± 


.26 


32 


32 


25.20 


* 


.19 



31 


40 


0U.88 


31 


40 


00.34 


31 


46 


58.85 


31 


46 


58.08 


31 


40 


59.70 


31 


19 


01.79 


31 


19 


57.94 


31 


19 


62.60 


31 


19 


56.86 


31 


19 


58.99 



31 19 69. 05 

31 19 06.07 

31 19 63.02 

31 19 57.58 



Arizona-Sonora. 
No monument. 
California. 



32 32 1. 34 



Mexican observations made at Monument No. OS ; Unit(^(l States observations made at Salazar's old monument, 
no east side of San Pedro River, and reduced to Monument No. 98 by triangulation ; hence Mexican result used. 



UNITED STATES AND MEXICAN BOUNDARY. 



SECTION y. 



lu order to identity the existing old momiineuts, as well as to obtain the necessary elements 
for locating tlie new monuments on the lines forming the boundary, the lollowing geodetic opera- 
tions were executed: 

I. Traciug the parallels according to tlie method of taugeuts and ofl'seta. 

II. Tracing- the meridian section by simple alignment, its direction having been previously verified. 

III. Tracing the azimuth lines, either by straight lines connecting consecutive existing old monuments directly, 
or by the aid of auxiliary lines starting at one of these monuments and passing as closely as possible to the next 
monument. 

IV. Triangulation made in the vicinity of the initial monument on the Rio Grande by the United States section 
to refer the initial mcpnumeut to its astronomical observatory, and the reference of the longitude of the initial 
monument to the astronomical station at Juarez made by the Mexican section by flash signals at night. 

V. Triangulation made in Nogalcs by the United States section and repeated by the Mexican section to refer 
Monument No. 127, at the west end of the line on parallel 31= 20', to the astronomical observatory occupied 
successively by both sections of the commission. 

VI. Triangulation made in the vicinity of Yuma, Ariz., by the United States section, and repeated by the 
Mexican section, to refer Monuments No. 20-1 and No. 207 to the astronomical observatory at Yuma, Ariz., occupied 
successively by both sections of the commission. 

All the preceding operations were executed independently and at difiereut epochs by the two 
sections of the commission, the results being compared as soon as practicable after reduction. 

On parallels 31° 47' and 31° 20' new monuments intervening between two consecutive existing 
old monuments were located upon a curved line joining the latter, the curvature of this line being 
as nearly that of the corresponding parallel as possible. 

On the meridian section and on the azimuth lines the new monuments were located upon the 
straight lines joining consecutive existing old monuments. 

In tracing straight lines, as well as in triangulation, heliotropes were generally used for 
distant signals. 

In the following tables are given the lines run by the two sections, respectively, and the 
measured oflfeets to existing monuments from those lines on parallels 31° 47' and 31° 20', and on 
the azimuth lines: 

PuraUel Sl° 47'. 



United States tangent 



On original survey. 



Mexican astronom- 

ital station No. 2 

Not shown 

Not found 



Not found . 
United States a 



No.2 

Not found . I 5 

United States astro- 



Monument No. 15 



Jnited States as- 
tronomical sta- 
tion No. 2. 



24.77 
122.46 
240.10 

22.91 



Meters. 
15.19 
15.00 



Monument No. 15 . Monuiuent No. 21 . 



Monument No. 15 



No. 21. 1 35.70 



30 



UNITED STATES AND MEXICAN ROUNDARY. 
Parallel ST- 47' — Continued. 



No. of monument. United States tangent. Mexican tangent. j 


On original survey. 


New 
No. 


No. 


Begins. 


Ends. 


Measured 
offset. 


NO. 


Begins. 


Ends. 


Measured 
ottset. 


United 
States. 


Mexi- 






26 
21 


3 

*3 
i 

4 
5 

5 

5 

5 


United States as. 
trononiical sta- 
tion No. 2. 


Monument No. 20. 


MHer.. 
58.40 

00. 84 
10.78 

0.00 
0.00 

2.44 
25.20 






Meters. 


nomical station 
No. 3. 

5 6 

United Statesastro- 
nomical station 










United States as- 
tronomical sta 
tionNo.3. 

do . ... 


Monument No. 21. 
do 


3 




JIoTiumentNo.40. 


0.95 


United States astro- 
nomical station 
No. 3. 

6 7 

7 8 

8 9 
United Statesastro- 

] nomical station 


2C 
33 
40 


do 


United States as- 
tronomical sta- 
tion No. 4. 
do 










I 
3 


Monument No. 21 . 


Monument No. 40. 


9.87 
60.72 


do 


do 


98.97 
63.11 




do 


^'o-* 1 


■■ 







> A check tangent was run from United Stales astronomical station No. 2 between Monuments Nos. 15 and 21, giving offsets of 4.14 and 
30.30 meters, respectively. Offsets to above points on parallel 31° 47' are aU measured to the north. 

Meridian lection. 
The line traced by both sections on the meridian section of the boundary was the straight line 
joining Monuments ]Sfos. 40, 40, and 53, which had been found to lie exactly in the meridiau. 

I'arallel St^ 20'. 



No. of monument. 




United States tangent. 


Mexican tangent. i 1 


On original survey. 


r 


No. 

8 
8 

8 
9 


Begins. 


Ends. 


Measured 
offset. 


No. 


Begins. 


Ends. 


Measurci 
offset. 


United 
states. 


Mexi- 
can. 


i 
10 11 

United States astror 


53 


United {States as- 
tion No. 5. 


United States a.s- 
tronomical sta- 
tion No. 6. 


— 6.49 
0.00 


' 


Monument No. 53 . 


Monument No. 64. 


Meters. 
0.00 




om- 




do 


. . 






United States astro 




do 


60.00 
0.00 










United States as- 
tronomical sta- 
tion No. 6. 


United States as- 
tronomical sta- 
tion No. 7. 








12 13 64 




Monument No. 04 . 
Me.xic.in astro- 

nomical station 

No. 7. 


98.64 
0.00 

— .57 
-129.29 

—118.80 
—108.56 









2 

2 
2 

2 


Mexican astro- 
nomical station 
No. 6. 

do 

do 


station No. 0. 


64 
65 

06 

67 

uom- 










13 

14 

15 

United Sta 


15 

16 

es astro 


9 

9 
9 

9 
10 


United States as- 
tionNo.6. 


United States as- 
tronomical sta- 
tion No, 7. 
do 


—118. 59 

-104. 01 
-90.20 

-94.24 
4.05 


do 


do 


do 






do 


do 










15 r ^'"Vr t'bt' 


United States as- 
tronomical sta- 
tion No. 7. 


United States as. 
tronomical sta- 
tion No. 8. 

























UNITED STATES AND MEXICAN BOUNDARY. 
Paralld SI- ^'6>'— Contiiiueil. 



31 



No. of monument. ] United States tangent. Mexican tangent. 


On original survey. 


Ne» 
No. 




Ends. 


MeasuredNo. 
offset. 




1 

Measured 
offset. 


United 1 Mejd- 
States. can. 


10 

10 

10 
10 

10 

11 


Begins. 


Begins. 


Ends. 




73 


United States as- 
tronomical sta- 
tion No. 7. 
do 

do 


United States as- 
tronomical sta-. 
tiouNo.8. 


Ueters. 
0.00 

37.51 

256. 58 

257. 32 

258. 13 
— 0.73 

0.00 








Meters. 


ical static 
16 

17 


nNo.7. 

17 


2 

2 
2 


Mexican astro- 

No.O. 
do 


Mexican astro- 
nomical station 
No. 7. 
do 


— 44.54 

196. 50 
198. 17 


do 












United States astronom- 
ical station No. 8 

18 19 1 V7 










United States as- 
tronomical sta- 
tion No. 8. 

do 


United States as- 
tronomical sta- 
tion No. 9. 

ilo 










United States astroi 
















11 


...:!::::::::::. 














M6\ic->u astronomj'-nl 








2 
3 


Mexican astro- 
nomical station 
No. 6. 

Mexican astro- 




Mexican astro- 


IJ') CO 


station No. 7. 

19 20 
Mexican astronom 


83 
cal 










nomical station 
No. 7. 

•MoTi.,,.,„.,f -Mn OB ' 1S7 11 










nomical station 
No. 7. [ 
do 1 do 


0.00 


United States astronom- 


11 

12 

12 
12 






138. 58 
0.00 


Do 


United States as- 
tronomical sta- 
tion No. 9. 


Monument No. 98 . 








StatiouA.tangentNo.ia. 
20 21 I 98 

1 
Station A, tangent No. 13. 


do 


59.06 
51.47 

0.00 








do 

Station A, tan- 
genfcNo. 13. 


MouumentNo.lU 


3 


Mexican astro- 
nomical station 
No. 7. 


Monument No. 98 . 379.78 

i 




4 1 Meviran atnlion 


1 1 
Monument No 111 n nn . 


station X 
20 

21 

22 

United Stat 


.8. 

21 \ 98 

22 106 


13 


Station A, tan- 
gent No. 13. 
do 


MonumentNo.lll 

do 

do 


— 7.62 
—110.33 


4 

■i 

4 

4 
4 


.^'i. 

do 

do 


do 

do 


.33 

-97.04 
- 89. 19 


es astronom- 


do 


do 


— 66. 18 

— 59.97 

0.00 

6.20« 


ilo 




23 24 lU 13 






:::::d: ;::::::::::; 




— 43. 01 


United States as- 
tronomical sta- 
tion No. 11. 


United States as- 
tronomical sta- 
tion No. 12. 




ical station No. 11. 


14 

14 
14 
14 

14 

15 

15 
15 


5 


Mexican .slatiou 
No. 9. 


Monument No. 127 


3.43 

0.00 


Mexic-tn as 
station Nc 


tronomical 








do 


do 




5 
5 


do 


do 








118.56 

17.17 
0.00 

12.33 
— 24. 63 






117.66 


United States astror 


cm- 










Do 


United States as- 
tronomical sta- 
tion No. 12. 
do 


Monument No. 127 










26 

27 


27 


122 
127 


5 


Mexican station 

No. 9. 
do 


Monument No. 127 
---•do 


29.70 
32.86 


do 


do 



Ou parallels 31° 47' and Sl*^ 20' ofle 



measured in th( 



= ToN. 
= ToS. 
1 lueridiau. 



UNITED STATES AND MEXICAN BOUNDARY. 

Sonora azimuth line. 

LDfES TRACED BY UNITED STATES SECTION. 



LINES TRACED 1!V MEXICAN SECTION. 

[-=ToS.] 



tho grealost oliaets to 



No. of monument on 
original survey. 


Now 
No. 


Begins. 


Ends. 


Measured 
offset. 


rnite.l 

States. 


Mexican. 


27 

XVIII 

XVII 

XVI 

XV 

XV 

XIV 




127 
129 
136 
137 
141 

141 
146 


127 


141 


Meters. 

0.00 

0.00 

—29.49 

—34. 20 


XVIII 

XVII 

XVI 

XV 

XV 
XIV 






1 




141 146 


-6.00 







.146 1m Munu 



, 204 tlie lines traced were practically tho straiglit lines joining the accepteil existiu 
California azimuth line. 



No. of monument. TTnitod States line. j Mexican lino. 


On origi- 
nal 1 New No. 
survey. , 


No. 


Begins. Ends. 


Meas- 
ured off- 
set. 


No. 


Begins. 


Ends. 


Meas- 
ured off- 
set. 


VII.... 

VI 

V 

IV 

IV 

HI 


(*) 

207 
220 
221 
221 


1 


Boundary post.... 

do 

do 


Between monu- 
ments Nos. 230 
and 231 


Meters. 

.00 

.00 

+32 55 








Meters. 






no 


do 


1 

2 


do 

do 

Monument No. 221. 

do 

Between monu- 
ments Nos. 230 
and 231. 

do 

MonumentNo.247 

do 


do 


+34 30 


do 


+30. 40 


do 

Between monu- 


+ 32.11 
+32 U 














menls Nos. 230 
and 231. 


—18. 32 
—25. 80 

+62. 20 

+62.20 

.00 


231 2 

247 2 

247 i 3 


ments Nos. 230 
and 231. 
do 

MonunicntNo.247. 
do 


MonumentNo.247. 

do 

MonumentNo.252. 
do 


-25.80 3 

+ 62.14 3 
+02. 14 ; 4 


MonumentNo.247. 

do 

do 


III ...1 2.')2 1 4 


Monument No. 252. 


Monument No II 


fin 








251 






5 
5 
5 


Monument No. 251 . MonumentNo. 258- 
do do 


+11.91 
+ 1.69 

.00 1 


II 


4 


Monument No. 252. 


Monument No. II. 


.00 




257 


do do 




5 


Monument No. II. 


Monument No. 258. 
do 


.00 
.00 


I 


258 


5 


MonumentNo. 251 MonumentNo. 258. - .57 



+ = ToN. +=ToN. 

— =ToS. — = ToS. 

■ Boundary post. 

Ou the Souora and (California azimuth liuus oflsets aro lueasureil at right angles to thu line as run. 
OPERATIONS OF THE MEXICAN SECTION. 

With the exception of some distances which, on account of the character of the country, 
were nieasnred directly by steel tape or by means of small triangles, the measurements along the 
boundary line were made by stadia. 

The offsets for points in tho parallel were measured with a steel tape in the corresponding 
meridian which had been previously laid oft' with a small theodolite. 



UNITED STATES AND MEXICAN BOUNDARY. 33 

OPERATIONS OF THE UNITED STATES SF.f'TION. 

Ou parallel 31° 47' distances along tangents were measured by both chain and stadia. All 
other distances along the boundary line were measured by stadia. 

The meridians in which were measured offsets to points in the i)arallels were obtained by 
turning off from the tangents angles dependent on the azimuth of the corrected tangent at the 
point. 

Offsets were measured with a steel tape in the meridian so obtained. All distances were 
reduced to mean sea level of San Diego Bay by means of a line of levels carried by the United 
States section from the Eio Grande to the Pacific. 

JdINT OPERATIONS. 

The triangulations made by the United States section and checked by tlie Mexican section at 
Monument No. 1, on the Kio Grande, Nogales, and Yuma, are as follows: 

DETERMINATION OF LONGITUDE OF MONX'MENT NO. 1, UNITED STATES TRIANUULATION. 

A base was measured on the railroad near Astronomical Station No. 1, and a triangulation 
laid out by the United States section from this base, connecting Astronomical Station No. 1 with 
Monuments Nos. 1, 2, audo, the magnetic station near ]MonumentNo. 1, the longitude station at El 
Paso; also with the public buildings in El Paso and Juarez. 

By this triangulation the difference of longitude of Monument I^o. 1 from the longitude 
station at El Paso is + L" 18.78", making the longitude of Monument N<'. 1, 100"^ ;U' 39.03". 

MEXICAN DETERMINATION BY PLASHES. 

The longitude of observatory at Juarez was transferred to Monument No. 1 by the Mexican 
section by flashes, the difference between those points being + 2' 45.75", making the longitude of 
Monument No. 1, 106' 31' 38.10". 

TRIANOULATION AT NOGALES. 

A base line of 724,90 meters was carefully measured at night on the railroad at Nogales, 
Mexico, and a triangulation made connecting the astronomical station at Nogales, Ariz., with the 
azimuth station and monuments Nos. 122 and 127. This triangulation was repeated by the 
Mexican section. 

l\esiiU« (if Iriangulation. 





Latitude. 


LongiUule. 1 




31 2U 4.70 
31 20 0.7.5 
31 19 59.30 




Monument No 122 


1 10 56 34 33 


Monument No 127 


111 4 34.46 





TRIANGULATION NEAR YUMA, ARIZ. 

A base of 2,203 meters was measured by the United States section, checked by the Mexican 
section afterwards, and an extensive system of triangulation made connecting the astronomical 
station in the corral of the United States Quartermaster's Department, occupied by both the 
United States and Mexican astronomical parties for latitude and longitude, with the azimuth 
station of both sections, with Monument No. 207 on we.st side of the Colorado River, and with 
Monument No. 204 on the east side of the same river 20 miles below the junction of the Gila and 
Colorado. This triangulation was repeated by the Mexican section. 
S. Doc. 247 3 



34 UNITED STATES AND MEXICAN BOUNDARY. 

The results of this triangulation are: 





I — 


Longitude. 




! - ,. 


114 37 23.40 
114 37 7.44 
114 36 56.61 
114 46 48.64 
114 43 54.31 








32 43 29 64 


Monument No. 204 


32 29 1.03 







Previous to commencing the erection of monuments it had been agreed that when the meridian 
of the site had been selected iu the field the corresponding distances from the pext preceding 
monument site to this meridian would be compared, and if found to differ more than one three- 
hundredths on parallel 31° 47', the meridian section, parallel 31° 20', and the Sonora azimuth line, 
or more than one flvehuudredths on the California azimuth line, they would be remeasured. 

Each section would then, from its own tangent or auxiliary line, lay off on the ground in this 
meridian the computed position of the monument. If the meridian distances of the points so located 
differed less than 2 meters it was agreed that the mean ijosition would be taken as the true position. 
Should this dift'erence exceed 2 meters the corresiJonding tangents or auxiliary lines were to be 
retraced. 

The agreed limits as to distances and oflsets were strictly adhered to except iu one case each — 
the discrepancy between the United States and Mexican measurements of the distance between 
Monuments 185 and 180 being one two-hundredand-seveutieth, and in their offsets at Monument 
191 being 2.04 meters. 

As both of these cases occurred on the desert, where water was difficult to obtain, and where 
remeasuremeuts would have caused serious delay, and as they exceeded the limit but slightly, it 
was considered best, in the interests of the work, to accept these discrepancies rather than to 
attempt remeasuremeuts under such adverse conditions. 

The distances between monuments obtained by each section sejiarately were compared, and 
the mean of the measurements of the two sections taken as the true measurement. This result 
was then reduced to mean sea level of San Diego Bay, California, by the usual geodetic formula, 
employing the elevations given by the line of levels of the United States section. 

The distances thus obtained (with the exception of those on the meridian .section) were 
adjusted — in the parallels to the astronomical longitudes of their extremities, and on the Sonora 
and California oblique lines to the astronomical longitudes of their extremities and the observed 
azimuths. 

The results of these reductions are shown in the following tables, and in addition are shown 
the difference, in a north and south direction, between the United States and Mexican locations 
of the monument site, and also the character of the monument erected. 



fii (lislanCL-s, in mctem, between 



ts on ],a -allel 31"^' 47'. 





Distance l)etwcen monnments. 


Reduc- 
tion to 

level." 


Reduced distances. 


Mex. 




No. of monument. 


United 
States. 


Mexican. 


Mean. 


To mean 
sea level. 


with astro- 
nomical 
distance. 


from 1J.. , „ ,„,„„, 

1 


1 














Masonry. 

Do. 

Do. 
Solid iron. 




4,202.76 
7, 568. 61 
7, 527. 66 
7, 930. 11 
7,703.02 
7,876.59 
1 400 39 


712.1 

7,563.5 
7, 533. 7 
7,931.6 
7,704.3 
7, 870. 1 
1,400.3 
7, 010. 9 
7,791.5 


711.89 
4, 260. 83 
7,566.05 
7, 530. 68 
7,930.86 
7, 703. 66 
7,873.34 
1,400.35 
7,011.03 
7,794,65 


— 0.14 

— .81 

— 1.48 

— 1.47 

— 1.65 

— 1.51 

— 1.54 

— .28 

— 1.37 

— 1.53 


711.75 
4,260.02 
7, 564. 57 
7,529.21 
7,929.31 
7, 702. 15 
7, 871. 80 
1,400.07 
7,010.26 
7, 793. 12 


713.4 
4,270.3 
7,682.7 
7,547.3 
7,948.3 
7,702.7 
7,890.7 
1,403.4 
7, 027. 1 
7.811.8 




3 






+0.36 


5 


6 


+ 1.04 Do. 
+ .94 Do. 
+ .03 Do. 




9 


10 

11 


7,012.36 
7,797.80 


—1.39 


Do. 
Mascmry. 



UNITED STATES AND MEXICAN BOUNDARY. 
Final distances, in meters, heticeen monuments on parallel Sl° 47' — Continued. 



35 



. of monument. 




Distance between monumentf 



5, 094. 78 
6, 920. 12 
4,671.24 
3,281.42 
1,657.06 



6,906.2 
4,675.2 
3, 284. 1 



5,094.79 
6,913.16 
4, 673. 22 

3. 282. 76 
1,656.88 

4, 339. 92 
3, 875. 05 



3, 970. 52 


3,969.2 


3,969.86 


3, 430. 65 


3,431.2 


3,430.93 


1,991.14 


1,99V 7 


1,992.42 


1,609.44 


1,610.2 


1, 609. 82 


4, 437. 34 


4,434.4 


4,435.87 


3, 815. 76 


3,820.9 


3,818.33 


1,328.39 


1,328.7 


1,328.54 


3,094.45 


3,092.1 


3,093.28 


3,523.44 


3, 531. 3 


3, 527. 37 


3,676.90 


3,675.7 


3,676.30 


4, 300. 20 


4,305.0 


4, 302. 60 


3, 430. 16 


3,427.0 


3,428.58 


2,433.47 


2,440.4 


2,436.93 


1,142.99 


1,144.3 


1,143.65 


4, 149. 30 


4, 160. 2 


4, 154. 75 


4,541.29 


4, 535. 


4,538.15 


3,700.68 


3,702.0 


3, 701. 34 


3, 000. 55 


2, 999. 


2,999.77 


2,592.28 


2,592.2 


2,592.24 


2, 775. 39 


2, 780. 7 


2,778.04 


2,053.88 


2,057.4 


2,055.64 



158, 828. 97 I 158, 858. 8 158, 843. 89 



level. 



Eeduced distance. 



with astro- 
nomical 
distance. 



Hex. 
from 
U.S. 



'e 




5, 093. 80 
6,911.82 
4,672.31 
3,282.11 
1,656.36 
4,339.09 
3,874.31 \ 
4,208.96 I 
3,969.11 
3,430.28 
1,992.03 
1,609.51 
4, 434. 99 I 
3,817.57 j 
1,328.28 
3, 092. 65 I 
3, 520. 65 

3, 675. 55 

4, 301. 72 
3,427.88 
2, 436. 43 
1,143.42 
4, 153. 85 
4, 537. 15 
3,700.53 
2, 999. 12 
2, 591. 68 
2, 777. 44 
2, 055. 19 



31.64 158,812.25 



3, 978. 6 
3, 438. 5 
1, 996. 8 
1,613.4 
4,445.6 
3, 826. 7 
1,331.5 
3, 100. 1 

3, 635. 1 
3,684.4 

4, 312. 1 
3, 436. 1 
2, 442. 3 
1, 146. 2 
4, 163. 8 
4, 548. 1 
3, 709. 4 
3, 006. 4 
2, 597. 9 
2, 784. 1 



+ 


.63 


- 


.31 




.00 


_ 


..38 


+ 


.28 


4- 


.81 


+ 


.62 


+ 


.08 


_ 


.14 


4- 


.01 


- 


.04 


+ 


.03 


+ 


.28 


+ 


.36 


_ 


.40 


- 


33 


...... 


"u 


+ 


48 


+ 


66 



Masonry. 

Solid iron. 

Do. 



Masonry. 
Solid iron. 



Masonry. 

Solid iron. 

Do. 



Final distances, in meters, hetwaen monuments on the Meridian section. 



No. of monument. 


Distance between monuments. 


Reduc- 
tion to 
meansea 


Distance 
reduced to 

level. 




Kindofmonu- 

Masoury. 
.Solid iron. 

Do. 

Do. 

Do. 

Do. 
Masonry. 
Solid iron. 

Do. 

Do. 

Do. 

Do. 

Do. 
Masonry. 


l^t Ue.icau. Mean. 


40 






1 




3,327.38 
4. 449. 05 
3,564.70 
3,689.32 
4, 747. 35 
4, 765. 63 
4, 773. 77 
3,894.98 
4,442.75 
4,381.53 
4,043.01 
3,321.38 
542. 20 


3, 329. 1 
4,448.4 
3,560.2 

3, 690. 96 
4,7.52.59 
4.751.0 
4,774.05 
3,l!82.4 

4, 443. .58 
4, 382. 88 
4,055.2 
3, 321. 2 


3, 328. 34 
4,448.73 


-0.71 1.3,327.63 


0.0 
.0 
.0 
.0 
.0 

.0 
.0 
.0 


42 




.95 


3,501.69 
.I, 689. 35 
4,748.99 
4,757.55 
4,772.91 

3, 887. 87 

4, 442. 25 




3,690.14 — .70 


43. 




4,758.57 
4,773.91 
3,888.69 
4,443.17 
4,382.20 
4,049.11 
3,321.29 


- 1.00 

- .82 

- .92 






49... 




51 


.92 .,ooi.^o 
— .85 4,048.26 




53 




542. 1 „,.,. i„ [ . i„ 1 j„. u„ 




49, 943. 27 






4 , 4. b 


' 




, - . 



36 



UNITED STATES AND MEXICAN BOUNDARY. 
Final distances, in meters, between monuments on parallel 31° SO'. 



Distance between monuments. 



3, 313. 58 
4, 987. 87 

3, 324. 08 
6, 096. 10 
1, 125. 31 

2, 529. 39 
3, 794. 68 

5, 679. 31 

4, 036. 72 

3, 487. 51 
1, 967. 75 
.■;, 987. 34 

4, 675. 14 
1,326.86 
1,797.34 
1,871.46 

6, 060. 61 
3, 983. 66 
4,449.98 
6,319.34 
0,685.44 
3,467.42 

3, 991. 16 
5, 153. 64 

5, 693. 59 

4, 46(1. 52 
3, 308. 49 
3, 474. 68 
3, 074. 18 



5, 114. 18 
2, 355. 49 

2, 787. 47 
6,492.22 
2,930.34 
1,527.71 

3, 559. 15 
3,330.01 
2,018.42 
2.682.37 
6, 120. 64 



3, 976. 70 
6,763.40 
2, 138. 4y 
3,613.50 
5,605.20 



6,469.70 
5,774.46 
2, 188. 43 
3,333.79 
4,011.83 
6, 168. 40 
5,401.90 
4, 803. 00 
3,313.60 

4, 979. 80 
3, 324. 29 
0, 084. 35 
1,128.98 
2, 533. 60 

3, 790. 80 

5, 677. 70 
4,031.20 
3, 478. 60 
1,965.88 

5, 987. 71 
4,681.49 
1,329.46 
1,795.05 

6,060.23 
3, 982. 49 

4, 437. 85 
C, 331. 68 

6, 684. 92 
3, 458. 70 
3, 990. ( 



4. 464. 65 
3, 309. 24 
3, 475. 46 
3, 073. 04 
3, 624. 14 
3,344.71 
4,990.13 
4, 853. 93 

441. S 
l,731.t 
5, 115. C 
2, 349. 64 
2, 790. 62 i 
6,470.68] 

2, 925. 70 
1,526.96 [ 
3.554.85 i 

3, 326. 10 
2.021.40 
2,675.87 
6, 106. 53 



3,981.09 
6, 768. 25 
2, 138. 12 
3,617.22 
5, 609. 66 
2. 092. 89 
6, 476. 55 
5, 774. 95 

2, T 90. 38 

3, 334. 02 

4, Oil. 83 
6,175.93 

5, 403. 80 
4, 808. 23 
3, 313. 59 
4,983.84 
3, 324. 18 

0, 090. 22 
1,127.15 

2, 531. 49 

3, 792. 74 
5,678.51 
4,033.90 
3,483.05 
1,966.82 I 
5,987.53 ! 
4,678.31 
1,328.16 

1, 796. 20 
1,870.34 
6,060.42 
3,983.07 
4, 443. 92 
6,325.51 

6, 085. 18 : 

3, 463. 00 
3, 990. 58 
5. 148. 47 
6, 693. 35 

4, 462. 58 
3, 308. 87 
3,475.07 
3, 073. 01 

3, 623. 94 
3,345.12 

4, 992. 72 
4,858.00 

442. 42 
1,729.37 
5,114.1 
2,352.57 
2,789.04 
6,481.45 

2, 928. 02 
1,527.33 

3, 557. 00 
3. 328. 05 



l^educed distances. 



To agree 
with as- 
tronomical 
distance. 



6,766.63 
2,137.61 
3,016.35 

5, 608. 32 

2, 092. 39 

6, 475. 00 
5,773.56 
2,189.86 

3, 333. 19 
4,010.89 
6,174.45 
5, 402. 51 

4, 807. 08 
3,312.80 
4,982.64 
3,323.38 
6,088.76 
1, 126. 88 
2,530.88 
3,791.92 

5, 677. 29 
4,033.09 
3,482.30 
1,966.40 
5, 980. 24 
4, 677. 30 
1, 327. 87 
1,795.81 
1,869.94 
6,059.11 



3, 462. 31 
3, 989. 72 
5, 147. 36 
5,692.12 
4,461.62 
3, 308. 16 
3. 474. 32 
3, 072. 95 

3, 623. 16 
3,344.40 

4, 991. 64 
4, 856. 95 

442. 32 

1, 729. 00 
5,113.53 
2,352.06 
2,788.44 
6,480.( 

2, 927. 39 
1,527.C 
3,556.23 

3, 327. 33 
2,019.48 
2, 678. 1 
6, 112. 27 



3, 981. 7 
6, 769. 3 
2,138.4 
3, 617. 8 
5,610.6 
2,093.2 
6,477.6 
5,775.9 
2,190.7 
3,334.5 
4,012.5 
6, 176. 9 
5,404.7 



Mex. 
U.S. 



^- 



6,091.2 I 
1, 127. 3 
2,531.9 j. 
3, 793. 4 



6,326.7 
6,686.4 
3, 463. 7 
3,991.3 
5, 140. 4 



3, 475. 7 
3, 074. 2 

3, 624. 6 
3,345.' 

4, 993. 6 
4,858.9 

442.5 
1,729.7 

5, 115. 6 
2,353.0 
2,789.6 

6, 482. 6 

2, 928. 6 
1,527.6 

3, 557. 6 
3, 328. 7 



--.19 
+ 1.14 



M.i.sonrj'. 
Solid iron. 

Do. 

Do. 
Sectional iron. 
Solid iron. 



.11 Section.-il iioi 



4, 034. 7 


-.37 


Do. 






Masonry. 
Solid iron 


1, 967. 2 


— .43 


5, 988. 6 


— .22 


Do. 


4,679.2 


—1.60 


Sectional 


1,328.4 


-.19 


Do. 


1,796.5 




Masonry. 


1, 870. 7 


-.44 


Solid iron 



Do. 

Do. 
Masonry. 
Solid iron. 
Sectional iron. 

Do. 

Do. 
Solid iron. 



Masonry. 
Solid iron. 
Maaonry. 
Solid iron. 
Do. 



UNITED STATES AND MEXICAN BOUNDARY. 



37 



meters, betiveen monuments on parallel 31° 20' — Continueil. 



No. of monu- 
ment. 


Distance between monuments. 


Reduc- 
tion to 

""level" 


Reduced distances. 


Mei. 

from 


Kind of 
monument. 


United 
States. 


Mexican. 


Mean. 


To agree 
To mean with as- 
sea level, tronomical 

distance. 


114 

115 

116 

117 

118 

119 

120 ... 

121 


1,994.22 
3,044.31 
3,862.46 
4, 145. 24 
1,865.96 
5, 149. 38 
2,471.31 
1,075.72 
256.70 
*I, 922. 09 
-3,062.83 
♦3,067.06 
*4, 403. 16 
231.82 


1.990.28 1,992.25 
3,046.91 \ 3,045.61 
3,862.43 3,862.44 
4, 141. 65 : 4, 143. 45 
1.864.60 1,865.28 
5,135.23 1 5,142.30 
2,471.31 2,471.31 
1,075.73 , 1,075.73 

256.70 256.70 

1.917.29 1,919.69 


— .43 

— .66 

— .83 

— .89 

— .40 

— 1.11 

— .54 

— .24 

— .05 
*— .40 


1.991.82 
3,044.95 
3,861,01 
4, 142. 56 
1,864.88 
5, 141. 19 
2,470.77 
1,075.49 
256. 65 
1,919.49 
3.062.71 
3, 066. 13 
4,403.45 


1,992.6 
3,046.2 
3,863.2 
4, 144. 2 
1,865.6 
5,143.2 
2,471.8 
1,075.9 
256.8 
1,920.2 
3,063.9 
3,067.4 
4,405.2 


— .31 
+ .48 
-1- .35 
-1-1.03 


Sectional iron. 

Do. 

Do. 
Solid iron. 
Masonry. 
Solid iron. 

Do. 

Do. 

Do. 

Do. 

Do. 
Sectional iron. 


-(- .63 

+ .04 
— .48 


m 


+ .65 
-1- .76 
+ .31 
— .31 




3,063.24 3,063.03 *- .64 
3,065.84 3,066.45 *- .64 
4,404.65 4,403.91 j *- .92 


125 

126 








Total 


273,017.51 


272,792.30 272,904.90 1 -60.77 272,845.43 272,954.2 



* Distances marked as above were determined by triaugalation. 
Final distances, ire meters, hetween monuments on the Sonora azimuth line. 



No. of monn- 


Distance between monuments. 


Reduc- 
tion to 
mean^sea 


Reduced distances. 


-S.) 


Kind of 


United 
States. 


Me-Kican. 


Mean. 


To mean 
sea level. 


To agree 
with as- 
tronomical 
distance. 


, 
















Masonry. 
Sectional iron. 
Masonry. 
Sectional iron. 

Do. 

Do. 

Do. 
Solid iron. 

Do. 
Masonry. 

Do. 
SoUdiion. 

Do. 

Do. 
Masonry. 
SoUd iron. 

Do. 

Do. 

Do. 
Masonry. 
Solid iron. 

Do. 

Do. 
Masonry. 
Solid iron. 

Do. 
Sectional iron. 
SoUd iron. 

Do. 

Do. 

Do. 

Do. 
Sectional iron. 
Masonry. 
Solid iron. 
Masonry. 




394.11 
5,647.28 
3,665.60 
5,688.13 
5,341.67 
2,528.45 
3,053.65 
6,173.87 

2, 529. 90 
4.236.79 
4,569.35 

3, 592. 49 
4,568.86 
2,028.56 
5,518.10 
5,632.46 

4, .535. 78 
5,523.13 
6,370.76 
7, 270. 59 

3, 884. 47 
4,663.77 
4,062.76 
3,606.87 
5,236.91 
4,557.97 
5,989.55 
5,294.19 
5,387.32 
4,668.84 
3,953.42 
3,840.63 

4, 069. 36 
1,989.95 
5,295.83 


393.51 
5.637.35 

3, 660. 18 
5,696.30 
5,354.61 
2,534.23 
3,045.46 
6,184.13 
2,533.84 

4, 240. 52 
4,565.38 
3,591.21 
4,569.25 

2, 028. 87 
5,524.90 

5, 631. 96 
4,531.78 
5,529.98 
6,369.38 
7,290.63 
3,892.10 
4,658.48 
4,053.55 

3, 604. 20 
5,237.71 

4, 569. 21 
5,977.44 

5, 293. 77 
5,379.85 
4, 662. 30 
3,952.35 
3,839.24 
4,061.88 
1,988.10 
5,281.81 


393. 81 
5,642.32 
3,662.89 

5, 692. 21 
5,348.14 

2, 531. 34 
3,049.55 

6, 179. 00 
2,531.87 
4,238.66 
4,567.36 
3,591.85 
4,569.06 
2,028.72 
5, 521. 50 
5,632.21 
4,533.78 
5,526.55 
6,370.07 
7,280.61 
3,888.28 
4,661.12 

4, 058. 15 
3,605.54 
5,237.31 
4,563.59 

5, 983. 50 
5,293.98 
5,383.58 
4,665.57 

3, 952. 88 
3,839.93 

4, 065. 62 
1,989.02 
5,288.82 


— 0.10 

— 1.33 

— ■'" 

I'-z 

— .59 
-1.21 

— .49 

— .77 

— .81 

— .63 

— .81 

::» 

— .77 

— .61 

— .75 

— .88 

— .94 

— .50 

— .60 

— .52 

— .34 

— .49 

— .56 

— .50 

— .51 

— .44 
_ .37 

— .36 

— .38 
_ .19 

1 - •^» 


5,640.99 
3, 662. 19 
5. 691. 10 
5, 347. 10 
2,530.85 

3, 048. 96 
6,177.79 
2,531.38 
4,237.89 
4,566.55 
3,591.22 

4, 568. 25 
2. 028. 36 

5, 520. 75 

4, 533. 17 
5,525.80 
6,369.19 
7,279.67 
3,887.78 

4, 660. 52 
4,057.63 
3,605.20 
5,236.82 
?,503.16 
5,982.94 
5,293.48 

5, 383. 07 
4,665.13 
3,952.51 
3,839.57 
4,065.24 
1,988.83 
5,288.32 


393.5 
5.638.0 
3, 660. 2 

5,344.3 
2,529.5 

3, 047. 3 
6, 174. 5 
2,530.0 

4. 235. 6 
4,564.1 
3,589.3 
4,565.8 
2,027.3 
5,517.8 
5,628.4 
4, 530. 8 
5,522.8 
6,365.8 
7,275.8 
3,885.7 
4,658.0 
4,055.5 
3,603.3 
5,234.0 
4,560.7 
5,979.7 
5,290.7 
5,380.2 
4,662,6 
3,950.4 
3,837.5 
4,063.1 
1,987.8 
5,285.5 






+ 0.01 
+ .18 
+ .06 
+ .04 
+ .01 
.00 


130 












'!! 


.00 
.00 




139 

140 


142 


.06 

— .15 
.00 




145 

146 


.00 

— .09 
.00 

.00 

.00 

.00 

-H.07 

-^- .05 

-1- .07 
-1- .18 

— .05 

— .06 










152 

153 

154 

155 

156 




158 






-f.02 


161 










38 



UNITED STATES AND MEXICAN BOUNDARY. 



Final (liatanceK, i 



Distance between monuments. 



1,968.40 
5, 197. 70 
0,084.31 

2, 945. 70 

4, 758. 30 
2,480,73 
5,05,^51 
4,467.84 
3,365.58 
4,475.31 

5, 781. 93 
3,275.28 
4,931.43 
4,286.88 
0,014.37 
7, 695. 93 
4,097.74 
5,705.80 
7, 713. 33 
7,298.47 
7, 907. 79 
4,215.93 
4, 496. 87 
4, 490. 74 

4, 007. 18 
7, 830. 22 

6, 278. 96 
3,554.76 
3,259.00 
3,139.33 
5,381.94 
5,726.85 
3,124.20 

5, 938. 12 

7, 240. 19 
7,776.79 
7, 597. 09 
7, 555. 07 
6,409.00 
4, 734. 12 
4, 067. 87 
4, 189. 56 

3, 000. 00 



1,967. .52 

5, 205. 03 

6, 085. 08 
2,911.98 
4, 747. 01 
2, 477. 06 
5, 046. 08 
4, 461. 05 
3, 370. 33 
4,467.08 



4, 284. 38 

6, 007. 58 

7. 688. 09 

4, 698. 41 

5, 696. 27 
7, 709. 49 



4,495.45 
4,513.41 

4, 003. 02 
7, 816. 14 

6, 204. 56 

3, 547. 80 
3,250.39 
3, 1.39. 33 
5, 375. 01 
5, 722. 94 
3, 127. 16 

5, 938. 15 

7, 228. 81 
7, 773. 80 
7, 593. 77 
7, 567. 29 
0, 396. 94 

4, 725. 07 
4, 058. 10 
4, 183. 50 
3, 000. 00 



376,099.6 375,906.6 376, 



1, 967. 96 
5,201.40 

6, 084. 09 

2, 943. 84 

4, 7.52. 05 
2,478.89 

5, 051. 10 
4,464.44 

3, 367. 95 

4, 471. 21 

5, 777. 66 
3,271.93 
4, 928. 27 

4, 285. 63 
0, 010. 98 

7, 692. 01 
4,698.07 
5,701.04 
7,711.41 i 
7,295.91 
7,902.57 
4,212.50 
4,496.16 
4,505.07 
4,005.40 
7,823.18 
6,271.76 

3, 551. 28 
3,254.70 
3, 139. 33 

5, 378. 48 
5, 724. 89 
3, 125. 71 

5, 938. 13 
7, 234. 50 
7,775.30 
7,595.43 
7, 561. 18 

6, 402. 97 

4, 729. 60 
4, 662. 98 
4, 186. 53 



Keduced distances. 



1, 967. 81 

5, 201. 01 

6, 084. 24 

2, 943. 03 
4, 752. 30 



4, 404. 19 

3, 367. 76 

4, 470. 96 

5, 777. 33 

3, 271. 74 
4,927.99 

4, 285. 43 

6, 010. 70 

7, 091. 00 
4,697.85 

5, 700. 78 
7,711.0.5 
7, 295. 57 
7, 902. SI 
4,212.31 
4, 495. 95 
4,504.86 

4, 005. 21 
7,822.82 

6, 271. 47 
3, 551. 12 

3, 254. 54 
3, 139. 19 

5, 378. 25 
5,724.06 
3, 125. !,9 
5, 9:17. 92 

7, 234. 27 
7, 775. 08 
7, 595. 25 
7, 501. 02 
0, 402. 87 

4, 729. 53 
4, 662. 92 
4,186.49 
3, 000. 00 



-31.46 ] 375,971.6 



To agree 
with .as- 
tronomical 
distance. 



Mex. 
V. S. pt. 



0, 048. 1 
4, 461. 8 
3, 366. 



5, 774. 2 

3, 270. 

4, 925. 4 
4, 283. 1 

6, 007. 5 

7, 687. 6 
4, 695. 3 
5,697.7 
7,706.9 I 
7,291.7 

7.898.0 I 
4, 210. 1 
4, 493. 5 
4, 5U2. 5 

4, 003. 1 
7, 818. 6 

6, 268. 1 
3,549.2 

3, 252. 8 
3,142.4 

5, 383. 8 
5, 730. 6 
3,128.8 

5, 944. 
7,241.7 
7,783.1 

7. 603. 1 

7, 568. 8 

6, 409. 5 
4,734.4 

4, 667. 7 
4, 190. 8 
3, 000. 



+ 2.04 
+1.96 



Masonry. 
Solid iron 



Masonry. 

Solid iron. 

Do. 



Sectional iron. 
Solid iron. 
Sectional iron. 



Sectional i 
Solid iron. 



Final distanoes, in meters, between monuments on the California azimuth line. 



No. of monu- 
ment. 


Distance between monuments. 


Kediic- 
tion to 
mean sea 
level. 


Eeduced distance. 


Mex. 
from 
TJ. S.pt. 
(+If. 
-S.) 


Kind of 
monument. 


United 

States. 


Mexican. 


Mean. 


To mean 
sea level. 


^itK« 
tronoraical 
(Ustance. 
















0.00 


Solid iron. 
Masonry. 
Solid iron. 

Do. 

Do. 

Do. 

Do. 

Do. 




809.04 

3, 348. 02 
0,364.66 
7,048.50 

4, 309. 53 
4,241.70 
4,718.03 


809. 73 
3,352.41 
6, 353. 99 


809. 38 
3,350.22 

R 359 39, 


0. 00 809. 38 

- .02 3,350.20 

— .08 : 6,359.24 

- .07 7,049.33 

— .03 4,313.73 

02 4 239 20 


809.4 

3, 356. 
6, 370. 2 
7,061.5 
4,321.2 

4, 246. 6 
4,729.8 


209 ... 


+ .92 
+ .40 
+ .50 
+ 1.48 
+ 1.14 
+ .38 


210 

211 


7,050.29 i 7,049.40 
4, 317. 98 4, 313. 76 
4 236 75 4 'aa 22 


213 


4, 725. 28 


4, 721. 66 


— .03 


4.721.63 



UNITED STATES AND MEXICAN BOUNDARY. 

Final distances, in meters, between monuments on the California azimuth Jim- — Continued. 



39 



Distance between mo 


numents. 1 


sea 
1. 


Reduced distance. 






" 


United 
States. 


Mexican. 


1 tion 


I^ZT^. 


^V^tK^ 

tronomioal 
distance. 


fiJ*- n,onmne1t 


6. 175. 85 


6. 181. 82 


6,178.83 1 — 


04 


6, 17S. 79 


6,189.5 


+ . 28 1 Solid iron. 




5. 379. 43 


5. 382. 96 


5,381.20 ; — 


01 


5.381.19 


5, 390. 5 


+ .22 


Do. 




6,588.48 


6,584.64 


6,586.56 ] _ 


01 


6, 586. 55 


6,598.0 


+ .32 


Do. 




6,461.52 


6, 467. 22 


6,464.37 — 


01 


6,464.36 


6, 475. 


+ .44 


Do. 




5,215.11 


5,214.71 


5,214.91 — 


01 


5, 214. 90 


5, 223, 9 


+ .36 


Do. 




4,713,20 


4,721.84 


4,717.52 


00 


4, 717. .52 


4,725.7 


+ .26 


Do. 




5,414.83 


5,407.42 


5,411.12 


00 


5,411.12 


5, 420. 5 




Sectional iron 




2,777.00 


2, 774. 16 


2, 775, 58 


00 


2, 775. 58 


2,780.4 


i Do. 




7,074.85 
5,178.35 


7,080.72 
5. 169. 00 


7,077.79 
5, 173. 67 


00 
00 


7,077.79 
5, 173. 67 


7,090.1 
5. 182. 6 


+ .04 
— .30 


Solid iron. 
Do. 




6,557.87 


6,558.38 


6,558.13 


00 


6, 558. 13 


6,569.5 


- .44 


Do. 




1 , 877. 03 


1,877.03 


1.877.03 — 


02 


1,877.01 


1,880.3 


— .52 


Do. 




4,359.80 


4,355.10 


4,357.45 - 


06 


4,357.39 


4,364.9 


— .66 


Do. 




4,292.76 


4, 285. 70 


4,289.23 — 


06 


4,289.17 


4,296.6 


— .26 


Do. 




5,868.36 


5,861.63 


5,865.00 - 


08 


5,864.92 


5,875.1 


- .52 


Do. 




5,007.86 


5,005.03 


5,006.44 - 


15 


5. 006. 29 


5, 015. 


— . 80 ! Sectional iron 




7, .524. .35 


7,516.71 


7,520.53 _ 


44 


7,520.09 


7,533.1 


- .98 Do. 




7,486.58 


7,472.60 


7,479.59 — 1 


11 


7,478.48 


7, 491. 4 


-1.24 1 Do. 




4, 924. 38 


4,933.40 


4, 928. 89 — 


83 


4,928.06 


4,936.6 


-1.18 Solid iron. 




4, 555. 62 


4,555.99 


4,555.80 - 


66 


4,555.14 


4,563.0 


-1.04 1 Do. 




4,097.08 


4,104.50 


4, 100. 79 — 


59 


4,100.20 


4,107.3 


— .98 Section.al iron 




4,099.58 


5,009.59 


5,004.59 — 


80 


5,003.79 


5,012.5 


- . 90 1 Do. 




3,620.45 


3,620.84 


3, 620. 64 — 


61 


3,620.03 


3,026.3 


— .08 Solid iron. 




4.154.26 


4,151.62 


4,152.94 - 


CO 


4,152.25 


4,159.4 


-.76 1 Do. 




2, 8B6. 08 


2,858.91 


2,857.50 — 


48 


2,857.02 


2.862.0 


— .70! Do. 




4,177.97 


4, 179. 99 


4,178.98 - 


69 


4,178.29 


4.183.5 


-.66| Do. 




3,055.94 


3,055.94 


3,055.94 — 


41 


3,055.53 


3,0C0.S 


— . 50 Do. 




1,859.92 


1, 861. 68 


1,800.80 - 


24 


1, 860. 56 


1, 863. 7 


— .58 


Sectional iron 




■ 4, 713. 90 


4. 710. 30 


4, 712. 10 — 


64 


4,711.46 


4,719.6 


— .12 


Do. 




5,122.38 


5,120.51 


5,121.45 - 


46 


5, 120. 99 


5, 129. 9 


- .48 


Solid iron. 




1,641.46 


1,641.49 


1,641.47 — 


16 


1,641.31 


1, 044. 2 


- .48 


Do. 




3, 649. 83 


3, 654. 90 


3,652.37 - 


34 


3,052.03 


3,658.4 


— .42 


Do. 




3,025.12 


3,031.58 


3,028.35 - 


37 


3,027.98 


3, 033. 2 


- .26 


Sectional iron 




864.54 


864.54 


864.54 - 


10 


864.44 


865.9 


— .20 


Do. 




3, 665. 12 


3, 665. 12 


3,665.12 — 


32 


3, 664. 80 


3, 671. 2 


- .20 


Do. 




3,103.51 


3, 106. 16 


3, 104. 83 — 


10 


3,104.73 


3. 110. 1 


— .22 


Solid iron. 




2,625.36 


2, 625. 36 


2, 625. 36 — 


08 


2, 625. 28 


2.629.8 


— .18 


Sectional iron 




6, 247. 04 


6,240.75 


6,243.90 - 


26 


6, 243. 64 


e,2,';4.4 


- .01 


Do. 




3,681.64 


3, 681. 64 


3, 681. 64 - 


15 


3,681.49 


3,687.9 




Masonry. 




5,498.50 


5,492.52 


5,495.51 - 


14 


5,495.37 


5,504.9 


.00 


Solid iron. 




3,555.48 


3,558.65 


3,557.06 - 


08 


3,556.98 


3,563.1 


.00 


Do. 




2, 461. 78 


2.401.78 


2,461.78 — 


03 


2,461.75 


2,466,0 




Crranite. 




4,932.79 


4,932.79 


4,932.79 1 - 


03 


4, 932, 76 


4, 941. 2 


.00 


Solid iron. 




2,350.58 


2, 350. .58 


2,350.58 ' — 


02 


2, 350. ,56 


2,354.6 


.00 


Do. 




1, 768. 52 


1,766.80 


1,767.66 - 


02 


1, 767. 64 


1,770.7 




Marble. 




226, 004. 79 


225, 997. 79 


226, 001. 29 —11 


55 


225,989.74 


226, 379. 6 



SECTION lO. 

METHODS USED FOR FIXING THE BOUNDARY IN THE ORIOrlNAX SURREY, 1819-1856. 

Astronomical determinations of the original survey. — In the first survey of the boundary line, 
in 1849-1856, there were established twelve stations for latitude and azimuth between the Rio 
Grande near El Paso and the Pacific near San Diego, and six of these — Paso del Norte, Oarrizalillo 
Springs, Nogales, Quitobaquita, Yuma, and Camp Eiley — were longitude stations. 

The results for longitude were obtained by observations of the transit of the moon and moon- 
culminating stars with telescopes of as large size as are usually used in field observations. 



40 UNITED STATES AND MEXICAN ROUND AKY. 

In all cases where it was uecessary to disclose the results on the spot — as at those stations 
at the extremities of the azimuth lines, and at stations such as the one hundred and eleventh 
meridian of longitude, which formed turning- points in the boundary — the longitude was deduced 
from computations based on the data atibrded by the Greenwich Ephemeris before receiving 
corresponding observations. 

Owing to the fact that the final values of these longitudes when computed, using correspond- 
ing observations at Greenwich and other observatories, diflered from that first obtained by the 
predicted place of the moon as much as nineteen seconds of time, the difference of longitude 
between stations computed from different data was also affected by a considerable error. 

THE METHOD OF BUNNINO THE LINES ON THE GROUND. 

The parallel of 31° 17', the meridian section, and parallel Hl° 20'. — The initial point of parallel 
31° 47' was determined by observations made by both sections of the original commission, and it 
was ascertained that the difference between the determinations of the parallel of 31° 47' made by the 
two sections was 0.84". It was mutually agreed to take the mean of the two results, and the point 
was ascertained and marked in the presence of both commissioners as the point where the parallel 
31° 47' strikes the river; that is to say, the point where the boundary under the treaty of Decem- 
ber 30, 1853, leaves the river to run westward. A tangent to the parallel 31° 47' was laid oft" and 
prolonged westward, and Monuments Nos. 2 and 3 were set by offsets from the same, using the 
Bessel spheroid to compute said offsets. 

An astronomical station was then established at Carrizalillo Spring, the water nearest to the 
end of the required 100 miles, and its latitude and longitude determined. "A monnment was then 
established on the road due south of the observatory, and the parallel extended in both directions — 
east, until it met, in the sand hills, the line produced from the Rio liravo; west, it was extended 
to the end of the 100 miles, and the parallel was obtained by measuring offsets from the tangent." 
(P, 30, Emory's report.) 

In regard to the determination of the length of the line along parallel 31° 47', the result can 
not now be verified from the records. According to agreement of both sections, stated in Major 
Emory's reportof the boundary, " the 100 miles was obtained by combining the observed longitude 
at Oarrizalillo and the distance actually measured. (P. 30, Emory's report.) 

Later, the Mexican section made a new survey of the parallel 31° 47', starting a tangent at 
Oarrizalillo and extending it in both directions, east and west, and, not finding the monuments 
numbered G, 5, and 4 by Emory, they constructed four new ones. Two of these were near the 
locations of Nos.G and 5 (Emory), but the other two were erected instead of Monument 4 (Emory). 
This explains the discordance in the numbers on the United States and Mexican maps; the former 
showing eight monuments on parallel 31° 47', and the latter nine. 

For the pui-pose of measuring the distance between the monuments, a triangulation was made 
by Sehores Molina and Oontreras, extending the chain of triangles executed by Sefiores Fernandez 
Leal and Herrera along the meridian section to Monument No. 4 (Mexican) only; consequently, 
the distance between Nos. 3 and 4 (Mexican) was never measured by either section of the original 
commission, and the whole distance from the initial monument on the liio Grande to Monument 
No. 9, at the extremity of the line on parallel 31° 47', was never directly measured. This is not 
surprising when the difficiulties are considered under which that survey was conducted — the 
principal being the hostility of the Indians and the lack of water and other supplies in this desert 
region. 



UNITED STATES AND MEXICAN BOUNDARY. 41 

The distances as shown by the United States and Mexican maps, coujparcd with the measured 
distances made by the present commission, are shown in the following tables: 

Comparison of Distances uetween Monuments, as Obtained from the Data Puxilisiied by the Commission 
OK lSt9-1856 with those Obtained by the Present Commission. 

Comparative distances on parallel 31° 47'. 



Monuments. 


Distances, 1849-1856. 




Difference from— 


United 
States. 


Mexican.! 1^92. 


United 
States. 


Mexican. 


I. (IE.) toll. (2E.) 


Meters. 
697 


Meiers. 
713 

4,278 
56,745 
19, 971 
21,500 
13. 192 
21, 628 


Meters. 
713 

54, 932 
20,007 
21,530 
13, 214 
21,656 


Meters. 
+ 16 


Meters. 

- 8 
—1, 813 
+ 36 

+ 22 

+ 50 
—1,747 


II (2E ) to III (3E ) 


4,217 


III (3E ) to IT 






V to VI (5E ) 




VI. (5B.) toTII.(6E.) 

VII.(6E.)toVIII.(7E.) 


12, G47 

21, 971 

22. 627 
98, 499 


+ 567 
— 315 
+ 243 
—2, 030 


3E to5E 


98 216 1 96 469 









Meters. 

(1) Length of line according to United States maps, 1849-1856 160, 658 

(2) Length of line according to Mexican maps, 1849-1856 - 160,847 

(3) Length of line according to present conimissiou 159, 193 

Difference between (1) and (3) —1,465 

Difference between (2) and (3) - — 1,654 

Meridian section. 

Meters. 

(1) Length of line according to United States maps, 1849-1856 49, 927 

(2) Length of line according to Mexican triangulation, 1S55 49, 881 

(3) Length of line according to commission, 1892 49, 928 

Difference between (1) and (3) — 1 

Difference between (2) and (3) —47 



PARALLEL 31° 20'. 

A tangent to parallel 31° 20' was started from Espia and carried to Ojo del Perro. From Ojo 
del Perro a new tangent was run in both directions; east to the meridian, which checked the one 
run west from Espia, and west to the San Luis Mountains. At San Luis Springs, about 30 miles 
west of the initial point of the boundary on parallel 31° 20', observations were again made for 
latitude and azimuth, and a new tangent was started in both directions; east to meet the one from 
Ojo del Perro, and west across the San Luis Valley and the Guadalupe Pass. 

The ne.xt astronomical station was established at San Bernardino Springs, and the third 
tangent produced east and west; east to check and connect with tangent No. 2, and west as far 
as the hills west of San Pedro liiv^er. The fourth astronomical station was on the Santa Cruz River, 
in latitude 31° 17' 5(i.33", and from here a point on the parallel of 31° 20' was obtained by direct 
measurement, and a tangent started in both directions. The next station was at Nogales, in 
latitude 31° 21' 00.48" and longitude 110° 51' 2.10" west of Greenwich. From observations at this 
observatory a fifth tangent was deduced, and extended by a separate party in both directions, 
running west until the one hundred and eleventh meridian of longitude was reached. Owing 
to the difficulties of the country the longitude was transferred by direct measurement and by 
triangulation. (See Emory's report, p. 31.) 

"The monuments erected on the line were of two classes: First, of dressed stone, laid without 
mortar; second, of round stones, undressed, forming simply mounds. 



42 UNITED STATES AND MEXICAN BOUNDARY. 

"Of tbe lirst, one was erected at the point south of the Carrizalillo, another at the intersection 
of meridian 108^ 09' 41.85" and parallel 31° 20', one at San Luis Springs, two at San Bernardino, 
one at San Pedro, one north of Santa Cruz, one where the line crosses (second time) Santa 
Cruz River, one at Los Nognles, and one at intersection of 111° and 31° 20'. Many mounds of 
the second das.s were erected, alway.s at points where the line crosses a road or trail. Mr. 
Salazar stated that he had erected, of dressed stone, in a permanent and durable manner, a 
monument at the initial jtoint on the Kio Bravo, and two monuments west of that point." (See 
Emory's Eeport, p. 32.) 

The following are excerpts fiom the journal of the joint commission, meeting of June 24, ISofi, 
page 37 of the report: 

Senor Salazar stated that after ho separated from Jlr. Emory, on the 20th of August, l><55, he reviewed with his 
parties the different Hues of the boundary; that is to say, the i)arallel 31*^ 47', the meridian, and the parallel 31° 20', 
on which lines the llexicau commission executed the following work: 

From the point south of El Carrizalillo, on which was erected a monument, he observed minutely on Polaris 
to determine the prime vertical ou both sides, east and west. The prime vertical and the parallel 31"^ 47' were 
connected by a triangulation, on the east side with that which had becu made at the initial point and on the west 
"side with the intersection of meridian. By this triangulati«m five points to the east were fixed, at which points he 
caused to be erected mouuuients of stone, with mortar, because he found not one established by the United States 
commission in said direction. 

The monument at the road was reconstructed of stone, with mortar. Upon all of them was inscribed the 
abridged inscription agreed npon. This line was then marked with ten monuments. That at tlie west itid he caused 
to be erected of dressed stone, with mortar, and inscribed with the complete inscription agreed upon, similar to that 
which was erected at the initial jioiut on the Rio Bravo. 

Mr. Salazar stated that he observed at the south end of the meridian for latitude and longitude, his results 
ditlering very little frcmi those of the United States commission ; that from this point was carried north a triangulation 
which was connected at the north end with that made on the parallel 31° 47', and was used to determine the position 
of said end (m the par.allel and on the meridian; that these two extreme points were left where the United States 
commission established them ; that having found no monument between them, he caused one to be erected intermediate, 
in sight of the Ojo de los Mosquitos, of dressed stone laid in mortar, with the usual inscriptions; that the monument 
at the south end was erected of dressed stone and mortar, with inscriptions similar in all respects to those at the 
north end and at the initial i)oint. Ou the parallel 31° 20', besides the observations he made at the intersection, 
he observed for latitude at San Luis Springs, at San Bernardino, and San Pedro River. He found monuments at 
the two first-named points, but none at the last; that his observations proved that the points were on the parallel 
31° 20', aud he caused monuments to be erected at these points with mortar, having the usual inscriptions upon them, 
and that ho thought it proper to erect a monument of the same kind in Guadalupe Pass. 

Mr. Emory stated his entire satisfaction with what had been done by Mr. Salazar, and gave his assent thereto, 
except with regard to the monument at San Pedro River. He desired to call in Mr. Weyss, who was with Mr. Von 
Hippel when the monument was erected on the San Pedro. His own recollection was, that a very substantial 
monument had been erected at the San Pedro by the United States commission. 

Mr. Weyss was brought before the commissioners, and stated that a monument of dressed stone, with the usual 
inscription, was erected on the p.arallel 31^ 20', three thonsaud eight hundred and twenty-five feet west of the San 
Pedro River. The maps aud views were exhibited showing the exact locality of this monument. Mr. Emory 
stated, if the Indians had destroyed that monument it was all very well; but if it was still standing, there might be 
some discrepancy, amounting, possibly, to 1 inch of arc, or 100 feet between the latitude of the monument erected 
by Mr. Salazar aud that erected under his orders. If so, it might hereafter, when the country was settled, produce 
confusion. 

Mr. Salazar stated, that in case both existed he would take the mimument erected by Mr. Von Hippel as the 
true boundary. Assented to by Major Emory. 

For a complete list of all the monmneuts of every description found, see table at end of this 
section. 

The monument erected by Major Emory on the west side of the San Pedro Eiver, and that 
erected by Senor Salazar on the east, were both found in 1892, aud their latitudes, by astronomical 
observations, were as follows: Senor Salazar's monnment, 31° 19' 35" (United States); Major 
Emory's monument, 31° 20' 3.02" (Mexican), and the latter was used to retrace aud mark the line 
in 1893. 



UNITKD STATES AND MEXICAN BOUNDARY. 



43 



Comparative distances on parallel St^ 20'. 



Monuments. 


Distances, 1849-1856. 


Bist^^^ces, 


Diflereuco from— 


United 
States. 


Mexican. 


United 


Mexican. 


XI (lOE) 


Meters. 


Meters. 


Meters. 


Meters. 


Meters. 




44, 390 
5,885 
4,8-5 
4,404 
20,156 
18, 127 
17,085 
67, 729 

23, 710 
4,192 
8, 082 

24, 623 
8,686 

12,916 


44,358 
5,861 
4,935 

20,192 
18, 087 
17 002 


46, 002 
6,176 
5,405 
4,809 
21,374 
16, 991 
IS ii\n 


+1,612 
+ 291 
-1- 530 
+ 405 
+ 1,218 
—1, 136 
-1,325 
+1,238 
+5, 055 


+ 1.644 
+ 315 
+ 470 
+ 478 
+1,182 
—1, 090 
-1, 242 
4 1,521 
+5,148 
+ 277 
+ 750 

— 767 

— 683 








xvn (16E) 




XX (19E) 




67.446 J 68,967 
23,617 28,765 


XXII CIE) 




XXIV (23E) 


8,157 8,907 + 825 
24,473 23,706 - 917 

9,611 8,948 : + 262 
12 893 12 fiSS 25R 






XXVIII (''7E) 











Meters. 

(1) Length of line according to United States maps, 1819-1856 264,860 

(2) Length of line according to Mexican maps, 1849-18.56 265, 142 

(3) Length of jine according to present commission 272, 954 

Difference between (1) and (3) -|-8, 094 

Difference between (2) and (3) +7,812 

The line from 111° longitude and .31° 20' Intitude to a point in the Colorado River, 30 miles heloio 
the junction of the Gila and Colorado. — By agreement between the two commissioners the western 
end of this line was located in the Colorado Eiver, 20 miles below the junction of the Gila and 
Colorado. No monument could be placed here, but in the direction of the line, 4,135,74 meters 
from the initial point. Monument No. II, of iron, was erected. 

Tlie position of this monument is given as latitude 32° 29' 1.48", longitude 114° 46' 14.43", 
and the azimuth of the boundary line at this point as 71° 19' 23.18" southeast to the monument at 
the junction of 31° 20' with the one hundred and eleventh meridian, as determined by the original 
commission. 

As this longitude was found by the pre.sent commission to be 111° 4' 34.45" and the longitude of 
Monument II, 114° 46' 48.04", the computed azimuth of the line became 289° 1' 14.96"=70o 58' 45.04" 
southeast, a difference of 20' 38". The length computed by the original commission was 382,844.87 
meters -4,135.74 meters =378,709.13 meters. The computed length in 1893 was 372,887.3, a differ- 
ence of 5,821.8 meters. 

After running the line for a short distance to the eastward the work was given up for want of 
water, and it was agreed that both parties cease work at the west end and proceed to the east end 
by the road along the Gila, the only available one at this season of the year, there to fix the point 
of intersection of the parallel of 31° 20' with the 111th meridian, as determined by the observed 
longitude of Nogales carried westward by triangulation and direct measurement. lu the latter 
part of August the instrument was placed in position and the azimuth (computed) of the new line 
(69° 19' 45.9" northwest) laid off, and the line was run by both United States and Mexican parties 
conjointly from peak to peak, marking these points by Monuments XIX, XTIII, XYII, XVI, XV, 
XIV, XIII, XII, XI, X, and IX. Monument IX stands on the Sierra de Sonoyta 14.5 miles from 
No. X, and about IJ miles north from the village of Sonoyta. The distance between monuments 
was determined by a rough triangulation consisting of intersections on prominent peaks, north 
and south of the line, measuring only the angles at the location of the different monuments and 
concludiug all others. 



44 



miTED STATES AND MEXICAN BOUNDARY. 



Ou the plain near Sonoyta a base was measured by the Mexican section and a connection 
made from this measured base with the line— Monuments IX to X — by four triangles with con- 
cluded angles, and from this line the distances between the other monuments to the eastward 
were computed. This triangulatlon was also carried westward to include Monuments YII and 
VIII, near the astrononucal station at Quitobaquita, and afterwards still farther west to Monu- 
ments VI and V. The distances obtained by triaugulation from the measured base were then 
adjusted to sum up equal to the distance from Monument VII to the eastern extremity of the 
line, as obtained by computing this length from the astronomical positions of the two ends, viz, 
Quitobaiiuita and the 111th meridian. 

The distance between Monnments VII and V, obtained from the triangulatlon from the 
measured base, was used uncorrected for the final adopted distance of Monument V from j\Ionu- 
ment VIl. 

The distance from Monument 1 1 to Monument IV was assumed to be that determined by the 
triangulatlon at Yuma. The sum of these distances, viz, Monument VII to V plus Monument II 
to IV, was then subtracted from the whole distance. Monument VII to Monument II, as obtained 
from the longitudes of Monuments II and VII, for the distance between Monuments V and IV. 

In 1893 neither Monument IV, on the Tinajas, nor Monument V, on the Tules, nor Monument 
III, on the desert, said to have been built a short distance east of Monument II, could be found, 
nor could anyone be found who had ever seen or heard of these monuments. 

The line of 1893 was therefore run by the United States section from Monument II to 
Monument VI, and afterwards carried eastward, from monument to monument, to its eastern 
extremity, now Monument No. 127. The Mexican section ran this line from the eastern end, and 
the location of points on the line between existing monuments where new monuments were erected 
in 1893-94 was determined by the data furnished by both surveys. The dilferences in the distances 
between the original monuments on this line, as determined by the fli-st survey in 1855, and those 
obtained by actual measurement in 1893, reduced to sea level and adjusted to sum up equal to 
the astronomical distance from Monument No. 204, on the Colorado River, to Monument No. 127, 
at the end of the line on parallel 31° 20', are given in the following table. 

The measured distance of stadia and triangulatiou reduced to sea level is 372,971.02 meters; 
the computed distance on broken line from the astronomical positions of the two ends, 372,887.3 
meters; the difference being 83.8 meters, or 1 in 4,550. 



'om2>araiive distances on Sonora line. 



Mouuiuent. 


Distance determined 
In— 


Difference. 


1849-1853. 


1892-1894. 






Meters. 


Meters. 


Meters. 










\1 


175, 026 


162,894 


- 12, 132 


I\ 


31, 379 


31,314 


— 65 


5 


23. 105 


23,415 


+ 10 


5 11 


6,974 


7,273 


+ 239 


SIII 


44, 699 


46,562 


+ 1,863 


SIV 


18,986 


19, 875 


+ 8S9 


sv 


26, 494 


27,565 


-t- 1,071 


5 VI . 


14, 593 


14, 746 


+ 154 


SMI 


3,519 


4,230 


+ 717 


5 VIII 


27 963 


28, 974 


+ 1,012 


3 IX 


5,262 


5,638 


+ 376 


P irallU -il" 2a 


409 


394 


— 15 



Metei 
Distance from Monument II to e\treiiut\ of lino on parallel il'J 20', according to United States maps, 

1849-1856 378,' 

Distance according to present commission 372, 1 

Dilfereuce 5,1 



UNITED STATES AND MEXICAN BOUNDAEY. 45 

Meastirements of the 20 miles from junction of the Gila and Colorado to initial point in Colo- 
rado. — We have by report of original commission the data to reduce to the junction of the Gila 
and Colorado, as then existing, the point selected by the commission in 1849 on the azimuth line 
joining the junction of the Gila and Colorado rivers with Jlonumeut I, on the Pacific. By the 
measurements then made this point was found to be 73.5 feet south and 1,070 feet west of the 
junction. It was originally marked by an iron monument, subsequently transferred to a point 
near the Colorado River on tlie new ArizonaSonora line, and called Monument II. 

If we admit that the post found in 1893 marks the point established in 1849, as all the testimony 
obtainable from old residents of Yuma seems to prove, we have the latitude and longitude of the 
junction of the Gila and Colorado 0.73" north and 12.53" east of the boundary post of 1893. 
Its latitude will therefore be 32° 43' 30.27" and longitude 114o 36' 44.08." Computing from 
Monument II to initial point in the Colorado Eiver by data of the original commission, giving the 
distance from Monument II to initial point as 4,135.71 meters and azimuth 108° 40' 36.82", we have 
latitude of initial point = 32° 29' 43.97", h)ngitude = 114° 49' 18.71". The positions of both junction 
and initial point are here given as derived from the observed latitude and longitude in 1893 at 
Tuma, transferred by triangulation to boundary post and Monument II. Computing the distance 
and direction of line from initial point in the Colorado to junction of Gila and Colorado, from 
latitude and longitude given above, we get the distance 32,171.4 meters, or 15 meters less than 20 
miles. Its azimuth is 217° 38' 53.06". 

The difference of latitude of the two points is, by original commission, 13' 47.85"; by present 
commission, 13' 46.30"; of longitude by original commission, 12' 34.78"; by present commission, 
12' 34.63". 

THE CALIFORNIA LINE FROM THE INIl'IAL POINT ON THE PACIFIC TO THE JUNCTION OF THE 
GILA AND COLORADO RIVERS. 

Emory's report, page 5, says : 

At the various conferences of the joint commission, the modoof conducting the survey was discussed; and it was 
agreed to determine the line by astronomical methods, as the only mode by which we could do so correctly and within 
our means. 

On page 144 the report says: 

The following is the order in which are arranged the subjects eiul)raied in the determination of the line: 

1. The longitude of Camp Riley, near the initial point. 

2. The longitude of camp near the, junction of the Gila and Colorado. 

3. The latitude of Camp Riley, near the initial point. 

4. The latitude of camp near the junction of the Gila and Colorado. 

5. Transfer of the latitude and longitude of Camp Riley, by triangulation, to the initial point. 

6. Azimuth of straight line from initial point, on Pacific, to Junction of Gila and Colorado. 

The comijutatious are given on pages 162-166, and on page 165 we find — 

Latitude of initial point on the Pacific 32 31 5il.63 

Latitude of junction of Gila and Coloriido 32 43 32. 2 

Difference of longitude 2 32 24. 9 

From our results for latitude and longitude in 1892 and 1893 we have — 

Latitude of initial point on the Pacific 32 32 1. 34 

Latitude of junction of Gila and Colorado 32 43 30.27 

Difterence of longitude 2 .30 47. 9 

The difference in the results for difference of longitude by original commission in 1849 and 
present commission in 1892 = 1' 37". 

Resulting azimuth at initial point on the Pacifii- by original commission 264 12 2.95 

Azimuth of line Monument I to Monument VI, 1893 264 10 50.33 

The line was run by the original commission from both ends toward the desert, and Monuments 
I, II, and III were erected near the west end and Monuments VI, V, and IV near the east end. 
The space between Monuments III and IV (82 miles) was unmarked. 



UNITED STATES AND MEXICAN BOUNDARY. 
Compuratire distances on California line. 



Monuments. 


Distance, 1849. 
Y^^^_ 1 Mexican. 


Distance, 
1893. 

Meters. 


Differenc 


e from— 


TJnitcd 
States. 


Mexican. 




Meters. Meters. 


Meters. 


Meters. 


IIT 


19,247 1 19,810 

145,823 144,109 

2.831 2,783 

57,418 1 54,931 


20,600 

132, 080 

2,780 

70. 918 


+ 1,353 
—13, 743 
— 51 
+ 13,500 


+ 790 

— 3 
+ 15,987 




V 







Meters. 

(1) Distance between Monuments I and VI, according to United States maps. 1849 225,319 

(2) Distance according to Mexican maps, 1849 221,633 

(3) Distance according to present commission 226, 380 

Difference between (1) and (3) 1,061 

Difference between (2) and (3) 4,797 

The Uuited States distances shown in preceding tables, of parallels 31° 47', 31° 20', and the 
California line, were deduced graphically from the United States maps of the original survey. 

The distances on the Sonora line were copied from the report of Major Emory, and agree with 
those given iu the manuscript report of Senor Jimenez. 

The Mexican distances along parallel 31° 47' were obtained from the tiiangulation made iu 
185") by Senores Contreras and Molina, with the exception of those between Monuments I, II, III, 
and IV, that were taken grai)hically from the ]\Iexican maps. The distances along parallel 31° 20' 
and California line were taken graphically from the same maps. 

The meridian section was obtained from the triaugulatiou made in 185.5 by Seiiores Fernandez 
Leal and Herrera. 



DIl-'FERENCES BETWEEN DETERMINATIONS OF LONGITUDE BY ORIGINAL COMMISSION AND 
THOSE OF THE PRESENT SURVEY. 

The following table gives the latitudes and longitudesof the principal points along the boundary, 
aud shows also the difference between the determinations of the original commission and those of 
1892. Two of these longitude differences have a material bearing on the location of the boundary 
as regards the area of territory lost or gained by either country in consecjuence of errors iu the 
first sui'vey. 

According to the treaty of 1S53, the parallel of 31° 47' north latitude shall be the boundary 
from the initial point on the Eio Grande where the parallel crosses the river; " thence due west 
100 miles; thence south to the parallel of 31^20' north latitude; thence along said parallel of 
31° 20' to the lllth meridian of longitude west of (Greenwich; thence in a straight line to a 
point on the Colorado IJiver 20 Phiglish miles below the junction of the Gila and Colorado rivers; 
thence up the middle of said river Colorado until it intersects the present line between the United 
States and Mexico." 

The length of parallel 31^ 47' was made by the original commission, from the initial x)oint in 
the Rio Grande to Monument 40, to be 1° 41' 57.55" (see p. 190, Emoi-y's Eeport), which is equal on 
Clark's Spheroid to 100,953.9 meters. The present survey made the length of parallel between 
the channel of 1853 — distant 71.04 meters from Monument 1 — and Monument 40, 159,264.4 meters. 
The survey of 1892 showed the channel of the Rio Grande to be 172.06 meters east of Monument 1, 
so that the length of parallel 31° 47' in 1892 was 159,365.5 meters. One hundred miles on parallel 
31° 47' equals 100,933 meters, so the parallel now is 1,567 meters short of 100 miles; and at the 
time of original survey the parallel was 1,068 meters short of 100 miles. 

Monument No. 127 was placed at the iutersectiou of parallel 31° 20' with the lllth meridian 
of longitude, as determined by the original commission. 

Our longitude of Monument No. 127, is 111° 4' 34.4", or 4' 34.4" too far west — equal to 7,254,2 
meters, or 4.5 miles. 



UNITED STATES AND MEXICAN BOUNDARY. 



47 



Tlie difference of longitude between tlie boundary i)ost at Yuma, and Monument 1 on the 
Pacific, was 2° 32' 24.9", as determined by tlie original commission in 1849. (Page 165, Emory's 
Keport.) By determination of 1892 it was 2° 30' 47.9". 

The distance from the junction of the Gila and Colorado to Monument I on Pacific, is 2,534 
meters less than that by the original commission. 

Comparison of latitudes and longitudes observed in 1S92~93 with those of the original survey in 1S49-1S56. 





Latitudes. Longitudes. 




1892-93. 1 1849-1856. j 1892-93. 1849-1856. 












31 46 59.70 60.00 I 108 12 29.67 108 l:i 24.05 
31 20 1.79 0.00 1 108 3 29.07 | 108 13 24.05 

31 19 59.30 60.00 111 4 34.45 HI 0.00 

32 29 1.00 1.48 114 40 48.64 114 46 11.43 
32 43 29.54 31.60 114 36 56.67 114 36 22.20 
32 31 61.34 59.63 117 7 31. S9 117 .S 29.70 















The differences in the results for longitude are due to imjiroved methods of observation and 
the use of the telegraph by the present commission. 



Original vwniimcnls. 
PARALLEL 31° 47'. 



No. of nioDument 
1 on original survey. 


No.whon 

„??etut 
in 1892. 


Distance 
ap„t. 


Description of monuments when sun-ey was made. 


United k. 

States. 1^ 


xican 








2liUs. 








1 
3 




Cutstone; pyramidal form ; square base; inscriptions; fair preservation. 
Koughly dressed stone; pyramidal form ; square base; no inscriptions ; poor 
preservation. 

Kouglily dressed stone ; pyr.lmidaU'ornn square lias.-; no iusoriptioiis; good 


2 
3 




0.4 
2.6 








11 


34.3 


preservation. 
Kough stones; mud mortar; pyramidal form; square l.ase; inscriptions; 








15 


12.4 


tumbling to pieces. 
Do. 


5 






21 


13.4 


Do. 


6 






26 


8.2 


Do. 


7 






33 


13.5 


Do. 


8 






40 


14.2 


Cutstone; pyramidal form : square liaae: in.scriptimis : L'wrl imservatiou. i 




99.0 



MERIDIAN SECTION. 



8 



10 


9 
10 

Jl 


40 
46 

53 




Cutstone; pyramidal form ; square base; inscriptions; good j.reservation. 

Hough stones; mad mortar; pyramidal form; square ba,se; inscriptions; ; 
poor preservation. ; 

Cut stone; pyramidal form; squarr base: inscriptions; .■xccllcut preserva- 
tion. 


15.2 
16.8 


31.0 





48 



UNITED STATES AND MEXICAN BOUNDARY. 



Original monuments — Continued. 
PARALLEL 31<= 20'. 





No.when 
repaired 
or rebuilt 
iu 1892. 


Distance 
apart. 










Miles. 




10 


11 


53 


0.0 


Cut stone; pyramidalforra ; square baso; iiisiriptimia: exnellentpi-eserration. 












12 


13 


64 


28.7 


Mound of loose atones; circular base ; height 4 feet; no inscriptions. 


13 


14 


65 


3.9 


Mound of loose stones; badly scattered; circular base; no inscriptions. [ 


U 


15 


60 


3.4 


Rough stones; mud mortar; pyramidal tbrui; square base; inscriptions; 
tumbling to pieces. 


15 


16 


07 


3,0 


Mound loose stones ; baiUy scattered ; square base ; no inscriptions. 


16 


17 


73 


13.4 


Loose stones ; pyramidal form ; square base ; inscriptions ; tumbling to pieces. 








10.5 


Loose stones; pyramidal form; square base; no inscriptions; fumbling to 
pieces. 










18 


19 


77 


.1 


Loose atones ; pyramidal form ; square base ; inscriptions ; tumbling to pieces. 


19 


20 


82 


9.9 


Pulled down ; apparently pile of loose stones ; round base ; no inscriptions. 


20 


21 


98 


43.1 


Loose stones; pyramidal form ; square base; no inscriptions; tumbling to 


21 


«o 


106 


18.0 


Loose stones; almost entirely demolished; no inscriptions. 


23 


23 


108 


2.8 


Loose stones; pyramidal form; sqmvrobase; no inscriptions; tumbling to 
pieces. 


23 


24 


111 


5,5 


Do. 


24 
25 


25 
26 






No trace remaining. 

Loose stones; pyramid;il form; square b;.se; no ins.iiiitiori.s ; tumbling to 


118 


14.8 










pieces. 


26 


27 


122 


5.6 


Loose stones; pvnuuid;il form ; siiuaru b;ise ; inscriptions; tumbling to pieces. 


27 




127 


7.9 


DO. 


170.6 





LINE J''ROM WEST END PARALLEL SI" 20' TO COLORADO RIVER. 



No. of 
monument 
on original 
survey. 


No. when 
repaired 
or rebuilt 
iu 1893-94. 


Distance 

apart. 


Description of monuments when survey was m;ide- 






mies. 




xis- 


128 


0.3 


Mound loose atones ; round base ; 3 feet high ; no inscriptions. 




xnii 


129 


3.5 


Loose stones; squaiebase; 25 feet high; no inscriptions. 




XVII 


136 


J8.1 


Mound loose stones; round base; 2Jfeethigh; no inscriptions. 




SVI 


137 


2.6 


Do. 




XV 


141 


9.2 






XIV 


146 


17.2 


Mound loo.se stones; round base; 5 feet high; no inscriptions. 




XIII 


150 


12,4 


Mound loose stones; round base; 4 feet high; no inscriptions. 




xir 


160 


29,1 


Mound broken lava; round base; 3 feet high; no inscriptions. 














X 


162 


4.5 


Mound broken lava; square base; ifeethigh; no inscriptions. 




IX 


168 


14.7 


Mound loose stones ; round baae; 4 feet high; no inscriptions. 




VIII 
VII 

VI 






No trace remaining. 

Do. 
Mound loose stones; round base; 3 feet high ; no inscriptions. 









175 


19.6 








No trace remaining; probably never erected. 

Do. 
No trace remaining. 




IV 

III 












II 


204 


101.8 


undermined. 


J 






No trace remaining. 






Initial 


1 








Pointed. 


2.7 








River. 


1 






235.7 



* It "was decided by tlie engineers in chief of the two sections that this monument was not suflSciently authentic, and 
it was not accepted. Mouument 128, however, was erected ou the lino joining Konument^ 127 and 129, and but 1.81 meters 
south of the center of this mound. 



UNITKD STATES^ AND MEXICAN ISOUNUAKY. 49 

Oni/inal i/i«»««ie>i/s— Ccmtinued. 
LINK FEOM THK (JOLOKAUO KIVEK To THK PACIFIC OCEAN. 

' Xo. of Xo. whuMi 

I mouuinent repaired Disfuuce Description ..f nwinumeiits wlieu survey w:,,s maile. 

oil original or rebuilt apart, 
survey. in 1894. 



0. 6 I Entirely i 
i-t. 8 ' Ca.st iron 



eniulisiietl; Itasc 



was iiI:K-e<l on a more jiernianeut site to the east of the old monuim-iil. 

SKCTIOX 11. 

TOl'DCiRAl'HY (>!•' UNITED STATES SECTION. 

By agreement between the eugiueers iu chief of the two .sections of the joint couiuiission. each 
section was to map the topographic features of a belt 2i miles in width on its own side of the 
boundary line, in such detail as would be necessary to plot the locations on field maps of a scale 
of 1 4- 30,000. 

To do this the measured distances along the boundary were used as bases, and stadia lines 
were run from the boundary, in a general northerly direction, to near the outer limit of the 
topographic belt, turning near this limit so as to cover most conveniently the principal topographic 
features in the vicinity, and then returning and closing on a located point on the boundary line. 
From these closed lines " spur lines" were run as needed, and from botli the closed and spur lines 
numerous secondary sights, giving azimuth, distance, and vertical angle, were taken. 

On both the closed and spur lines backsights and foresights were always taken, and at each 
of these sights the a/iniuth, the distance and vertical angle were read. The maximum error in 
distance allowed on closing was one three-hundredth, and in elevation one decimeter per kilometer 
per degree of average vertical angle of the courses of the Hue. 

In some cases locations were made by intersections, and occasionally the topogra[>hy was 
"filled in'' from located points by anl of tlie prismatic comjjass, hand level, and sketching. 

Between the Pozo Verde Mountains and the Colorado Elver, a distance of more than ;!23 
kilometers, the region bordering the boundary line is ditticult of access, remote from railroads, is 
practically uninhabited, and is a true desert, containing but five badly spaced permanent watering 
places in the entire distance. 

Owing to these causes, and in order to expedite the work in this inhospitable region, it was 
decided that between the west end of parallel 31° 20' and the Colorado Eiver a topographic belt, 
1 kilometer iu width, adjacent to the boundary line would be surveyed and plotted in the usual 
manner, but that the remainder of the L'i mile belt of topography would be taken by placing (lags 
on all of the prominent peaks, ridges, and other natural objects, to be located by the transit man 
engaged in measuring the boundary line. Another transit man would then occupy these positions 
and from them locate all flags in .sight. Other important topographical features were then to be 
located, either by stadia or by resection, and contoured sketches of the immediate vicinity made. 

Datum points for elevations were given by a line of levels carried along the boundary from 
the Kio Grande to the Pacific, and connected at VA Paso, Tex., and Yuma, Ariz., with bench marks 
of the Southern Pacific Railway and at San Diego. Cal., with a bench mark established by the 
United States Coast and Geodetic Survey. 
S. Doc. 247 4 



50 UNITED STATES AND MEXICAN BOUNDARY. 

The datum ])hiiK', was that of mean sea level of San Diego Bay, California. 

(treat care was taken in running the line of levels. The rods were held on iron pins driven 
firmly in the ground. Equal foresights and backsights were taken, and at each setting of the 
instrument both of these sights were read until two values of each were obtaiued which did not 
differ more than 1 millimeter, the rod being undamped and reset after each reading. The mean 
of the two values thus obtained was taken as the true reading. 

Most of the topographic notes were reduced in the field by the observers who took tlieui, and 
about half of the field sheets were plotted there; tlie rest were plotted in the ofBce either by the 
assistant engineers in charge of topographic work in the particular region or by an assistant 
engineer i)ersonally familiar Mith it. 

TOPOGRAPHY OF TIIK MEXICAN .SECTION. 

From the initial monument on the KioCrraude to Monument 111 (XXIV) the method employed 
was to determine, by intersections from different points on the tangents, the most prominent 
jtoiuts of the ground, the lines joining these points then constituting bases from which other 
points were fixed by intersections. At some of these points conveniently selected, sketches of 
the ground were made to complete the configuration. In some places polygons were run with 
bearings and distances, having as bases points on the tangents or referred to said tangents, meas- 
uring the distances with tape or stadia. The heights were determined by vertical angles. 

From Monument 111 to 253 on the Pacific Ocean the method of detail employed was a series 
of polygons, run by bearings and distances by means of a field compass and odometer on wheels 
run by hand, said polygons having as a base two consecutive monuments of the boundary. From 
several points of these polygons sights were taken to the most prominent points of the ground to 
fix them by intersections, and a sketch of the ground was carried of 1 kilometer in width on 
each side of the line of the polygon. 

The heiglits were determined Avith aneroids and vertical angles. Each polygon was run so 
that it would take in the most important details of tiie ground, and was selected to obtain the 
best points of view for the sketches. 

At the Colorado River a special survey was made by a chain of triangles along its banks 
and 180 vertices were locatetl exactly on the banks of the river. Of these vertices one-half were 
on the American side and the other half on the ^Mexican side. 

The angles of the triangulation were measured with two theodolites reading to J minute, 
repeating each angle twice in both positions of the instrument. 

The first base for the triangulation was measured on the line ont from Monument 206 to 
Monument 207, and its azimuth obtaiued from the line of said monuments. The triangulation was 
carried on to Monument 205. Four bases of verification were measured at nbout every 45 triangles, 
and every section of the chain was computed from its own measured base. 

The islands were surveyed by polygons lying oii the vertices, measuring the distances with 
metric tape, when the polygons were small, or with odometers upon handwheels, when they were 
large. By the same method the main estuaries were surveyed and other polygons were run in the 
valley of the river so as to take in the detail of the Mexican side and make sure that no detail 
was hidden by the vegetation. 

The final results of the triangulation were computed with the ditterences of geographical 
coordinates, between Monuments 205 and 207, and were compared with those obtained for the 
same points by the geodetical work of the commission. The following differences were found; 

l)iHeren.<!<.f latitude by Mexican tiiannulatioii in lSil4 13 29.9 

Diti'cieMci! of latitude by bouud.iry survey tiiausulaf ion iu 18915 13 29.6 

I)ise.e,.an<y 0.3 

Dift'ereuce of longitude by Moxicau tiiangulation in 1894 i 42. 3 

Difference of longitude by boundary survey triangulation iu 1893 i 43. 3 

DiHerepauey " 1-*^ 

The projection of the map was adjusted to the positions of the boundary survey. 



UNITED STATES AND MEXICAN BOUNDARY. 51 

SECTION 12. 

As provided at the meeting of tbe joint commission held in San Diego June 19, 1894, the two 
Governments were informed of the necessity for an extension in the time of the last convention to 
enable tbe commission to fully complete its labors, including the preparation of the final maps and 
reports. In compliance with this request a convention between the United States and Mexico 
was signed at Washington on August 24, 1894, and duly ratified by the respective Governments. 

Following is a copy of this convention : 

Whereas the Unitfd States ot America aud the Lniti-d States of ilcxicu desire to comply fully with the ino- 
visions of the couventioii concluded and signed at Washington July 29, 1882, ])roviding for an international boundary 
survey to relocate the existing frontier line between the two countries west of the Rio Grande; and 

Whereas the time fixed by Article VIII of that convention for the termination of the labors of the Interna- 
tional Boundary Commission, as extended by Article II of the convention, concluded and signed between the two 
high contracting parties February 18, 1889, will expire October 11, 1894; and 

Whereas the two high contracting parties deem it expedient to agree upon a further extension of the time 
stipulated in Article II of the convention aforesaid, to the end that the International Boundary Commission may be 
enabled to finish all its work and so render a report, accompanied by a final map of the topography on both sides of 
the line, they have appointed for this purpose their respective plenipotentiaries, to wif ; 

The President of the United States of America, Walter Q. Gresham, Secretary of State of the United States of 
America, and 

The President of the ITnited States of Mexico, Matias Romero, envoy extraordinary and minister plenipoten- 
tiary of the United States of Mexico in Washington, 

Who, after having communicated to each other tlieir respective full jiowers, found in good and due form, have 
agreed upon and concluded the following article : 

AirricLE I. 

The period fixed by Article VIIl of the aforesaid convention of .Inly 29, 1882, between the United States of 
America and the United States of Mexico, which was extended for five years from the date of the exchange of the 
ratifications of the convention of February 18, 1889, between the same high contracting parties and which will 
terminate October 11, 1894, is hei-eby further extended for a period of two years from that date. 

This convention shall be ratified by the high contracting jiarties in conformity with their respective constitutions, 
and its ratifications shall be exchanged in Washington as soon as possible. 

In faith whereof, we, the undersigned, in virtue of our respective full jiowors. have signeil this convention, in 
duplicate, in the English and Spanish languages, and have thereunto afiSxed our respective seals. 

Done at the city of Washington, the 24th day of August, iu the year 1894. 

Waltk.ii Q. Ghesham. [seal.] 
M. Romero, [seal.] 

.KH'BNAL OF THE .JOINT COMMISSION (CONTINUED). 

In accordance with the resolution adopted at the last previous meeting in San Diego, Cal., 
October 8, 1894, the International Boundary Commission, United States and Mexico, met at the 
State Department, Washington, D. C, at 11 a. m., October 11, 1895, and, after being presented to 
the Secretary of State, adjourned to meet again on October 15, 1895. Present: Col. J. W. Barlow, 
United States Corps of Engineers; Senor Jacobo Blanco, engineer in chief of the Mexican section; 
Mr. A. T. Mosnian, assistant, United States Coast and Geodetic Survey; Seilor Valentin Gama, 
assistant astronomer, and Lieut. D. D. Gaillard, United States Corps of Engineers. Absent: 
Senor (iuillcrmo B. y Puga, probably en route from Mexico. 

Jacobo Blanco, .1. W. Baklow, 

Inffo. en Jefe, cle la tSeccinn Mexico. (Jolontl of En(/meers, U. S. A. 

Valentin Gama, D. D. Gaillard, 

Adjunto Astronomo. First Lieutenant of Engineers. 

A. T. Mo.SMAN, 
Assistant, Const and Geodetic Survey. 



At a meeting of the International Boundary Commission held in the offices of the commission 
in Washington, D. C, October 23, 1895, there were present all of the members. The proposed 
meeting of October 15 had been informally postponed by mutual consent while office rooms were 
being prepared. 



52 UNITED STATES AND MEXICAN BOUNDARY. 

It was agreed that the ncale of tlie final maps of the joiut commission shall be one 1-^00,000; 
tl)at the distance between contours shall be 20 meters; that the projection used shall be the 
polycouic; that the interval between meridians and parallels shall be five minutes of arc, and 
that the center meridians shall be perpendicular to the lower edges of the sheets, which shall 
be 1 meter in length. Natural features of the country shall be designated by their local names. 
As a basis for plotting the mai)S the horizontal distances between monuments already agreed upon 
will be used. Elevations will be»determined by the level line run by the United States section 
between the liio Grande and the Pacific. The title on each sheet shall be both in Kuglish and 
Spanish. 

It was also agreed to adopt the changed distances between Monuments 25'i-2r>.5 and 25."»-2r)(>, 
and to modify the tables to conform to the new position of Monument 255, as relocated by the two 
engineers in chief after its destruction in January, 1895. 

J. W. Bai;low, jACono Blanco, 

Colonel of Eni/iiiirrn, ('i>miiiiKsi<»tcr. Inyo, en Jefe, de la Hevcion Mcx. 

1). D. Gaillakd, Valentin Qama, 

Firnt Lieut, of Knijhueni. Adjuiito Astrouonio. 

A. T. MdSMA.N, GriLLKKill) 15. Y PlTGA, 

As.si.stdiitj Coa t (iikI (Iciidclic iSnrrc.i/. Adjiinto Aatrouomo. 

At a meeting of the commission held January 10, 181U!, a general form lor tlie joint report was 
agreed upon, which has been substantially followed in writing the re])ort. 

At a meeting of the International Boundary Commission, between tlie United States and 
Mexico, held in Washington, 1). C, on January 23, 189G, all the members being present, it was 
agreed, subject to tlie approval of the two Governments, to have the 20 sheets of the joint 
map of the survey of the United States and Mexican boundary, from the I»io Grande to the Pacific, 
engraved upon copper, tlie expense, approximately $8,000, United States currency, to be equally 
divided. 

Jacoiso I'.lanco, J. W. Baulow, 

Ingo. en Jefe, de In Seccion Met: Colonel of Engineers, U. 8. A. 

Valentin Gama, D. D. Gaillard, 

Adjiinto Astronomo. Captain of Engineers, U.S.A. 

GUILLEKMO B. Y PTJGA, A, T. MOSMAN, 

Adjiinto Astronomo. Assistant, Coast and Geodetic Siirvei/. 

Washington, D. G., February 34, 1896. 
At a meeting of the joint commission held this day, at which were present all of the members, 
it was agreed that the part of the joint report relating to astronomical observations (latitude, 
longitude, and azimuth) should consist of: 

First. A table containing the final results of the determinations made by the Mexican section 
of tlie commission with their probable errors; the method of observations; the number of nights 
on which observations were taken; the number of observations, and the name of the observer. 

Second. A similar table, giving the corresponding results obtained by the American section 
of the commission. 

Third. A table of means and flii;il values adopted by tlie International Gomniission. 
Jacobo Blanco, j. w. Barlow, 

Ingo. en Jefe, de la Sercion Me,v. Colonel of Engineers , 

Valentin Gama, Engineer in Chief of the American Section. 

Adjunto Astronomo. 1). D. Gaillard, 

Guillermo B. y Puga, Captain of Engineers, U.S.A. 

Adjunto Astronomo. A. T. Mosman, 

Assistant, U. S. Coast and Geodetic Survey. 



UNITED STATES AND MEXICAN i;OUNDARY. 



53 



st:ctjon 13. 

construction of the jmaps of the boundary. 

The field maps of the topography were mule, as described iu section 11, on a scale of 
1-^30,000, tiie part on the north of the bouuda'y of a width of 2| miles by the United States 
section, and the part south, of the same width, by the Mexican section; the width of the entire 
belt plotted being 5 miles. 

At a meeting of the joint commission on October 23, 1895 (see section 12), it was agreed that 
the scale of the final maps shall be 1-^60,000; that the contour intervals shall be 20 meters; 
that the projection used shall be polyconic; that the intervals between meridians and i)arallels 
shall be five minutes of arc, and that the center meridians shall be perpendicular to the lower 
edges of the sheets, which shall be 1 meter in length. 

As a basis for plotting tlie maps the horizontal distances between monuments shall be used. 
Elevations will be determined by the level line run by the United States section. 

Before beginning the maps it was agreed tliat a mean parallel of latitude should be adopted, 
which should be the mean of all the observed latitudes along the boundary, and that the horizontal 
distances between monuments given in the tables of section 9, together witli the mean latitude, 
should govern their location. 

The topography of the 2^ miles to the north of the line was then drawn in pencil, reduced 
from the field maps of the United States section, by the United States draftsmen. The topography 
of the 2.J miles south of the line was also drawn in pencil, reduced from the field maps of the 
Mexican section, by the Mexican draftsinen. The maps in pencil were then carefully compared 
before inking. 

The land boundary between the Rio (irande and the Pacific was contained in 18 sheets. A 
sheet (numbered 19) was then drawn for the Colorado River section. As the river and the eastern 
side had been surveyed by the United States section in March, 1S93, and the river and the western 
side by the Mexican section in February and lAIarch, 1891, the two representations of the river do 
not correspond,* so both are shown on sheet No. 19 in difterent colors. 

In the following table column i shows the observed latitudes at nineteen stations along the 
boundary called A, and column 3 the mean geodetic latitudes resulting called G; column 5 shows 
the difference G — A, or the derived "station errors" in latitude of all these nineteen stations. 



Mean geodetic latitudes, reduced to mean of United States and Mexican obseried latitudes on whole tin 



Moiinmenta. 


Mean geodetic 
S = G. 


Observed 

S-=A. 


G — A. 




1 Olil No. 


Xe«- No. 




J 


1 


31 


46 61.35 


31 


46 59.40 


+1. 95 


On EiO Grande. 








60.95 




60.88 


+ .07 


Mex. Station No. 2, oude.-ert. 


5 


15 




60.54 




60.34 


+ .20 


Near Wragg's Kanch. 


a 


21 




60.62 




58.85 


+ 1.77 


Near Columbus. 


7 


26 




60.56 




.58.08 


+2.48 


Near Carizalillo Springs. 


9 

11 


40 


31 


60.59 
19 59.48 


31 


59.70 
19 61.79 


+ .89 
-2.31 


Upper corner. 

Lower corner. 1 


13 


U 




59.27 
59.29 




57.94 
62.60 


+1.33 U.S.Sta.No.6,nearWliilewater. 
-3.21 Mexican Statioi. No. 6. 


16 

19 


67 
77 




55.52 
61.51 
60.85 
62.89 




56.86 
58.99 
59.65 
60.07 


—1. 34 ! Near Lang's Rancli. 

+2.52 San Bernardino. 

+1.20 Max. Station No. 7, Niggerhead. 

-3.18 U.S.Sta. No. 9, Dutch Charleys. 


21 


98 




62.13 




63.02 


-.89 ' SauPedru. 


2i 


111 




57.83 




57.58 


+ .25 Lanoria. 


11 


122 
204 


32 


57.03 
29 2. 16 


32 


60.75 
29 1.00 


—3. 73 Nogales. 

+1. 10 East bank Colorado Kiver. 






32 


43 35.85 ■ 


32 


43 34.69 


+1. 16 U. S. Station No. 13, Yuma. 


I 


258 


32 


32 1.01 


32 


32 1.34 


-0.33 On Paciflo coast. 



* The difference in the two representations of the river arises from the fact that the bed of the river changed betv 
United States survey in 1893 and that of the Mexican survey in 1894. 



UNITED STATES AND MEXICAN BOUNDARY. 
Meau lalitiidea and longiliides of monnmeiUs on pu^-iilhd Sl^ 47 



Mean la 


itn.le. 


Longitude. 


'No. 


Mean hi 


itmle. 


Longitude. 


Old. 


New. 


, 


V 




„ ' 






/ 




^ 






31 40 


01.35 


106 


31 


39.03 


6 


21 


31 40 


60.62 


107 


35 


55.08 




fil. 35 




32 


6.15 




22 




60.01 




37 


10,98 




CI. 35 




34 


48.40 




23 




00. 00 




38 


12. 30 




fil. 23 




39 


36.60 




24 




6". 58 




41 


1.27 




01.11 




44 


23.51' 




25 




00.57 




43 


26.71 




00.98 




49 


25.01 


7 


20 




00.50 




44 


17.32 




no, 8.-I 




54 


19.01; 




27 




00. 50 




46 


15.15 




00.72 




59 


18. 9V 




28 




00.50 




48 


29.51 




CO. 70 


107 





12.31 




29 




60. 57 




50 


49.55 




00.59 




4 


39.40 




30 




60. 58 




53 


33.44 




60. 4e 




9 


36.31 




31 




60.58 




55 


44.04 




60.48 




12 


50.38 




32 




60.58 




57 


10.87 




60.51 




17 


13.71 


8 


33 




GO. 58 




58 


0.44 




60.53 




20 


11.73 




34 




00. 58 


108 


u 


38. 69 




60.54 




22 


10.77 




35 




60. .^.9 




:i 


31.50 




r,o. .^5 




23 


19. R8 




30 




CO. 59 




5 


52. 55 




oil, .'•.7 




-O 


.-.. -ri 




37 




CO. 59 




7 


40.81 







Mean liiiitudes 


and longitudes of monument 

Longitude. 

Old. New. 


s on parallel 31 
Mean latilude. 


SO'. 


X 

Old. 


New. 


Mean lalitn.le. 


Longitude. 


11 


53 


31 19 59.48 


108 12 29.67 




91 


31 19 61.95 


109 ,52 24.96 




54 


59.47 


15 0.28 




92 


01.98 


50 0. 35 




55 


59.40 


19 16.34 




93 


C2. 02 


58 49.19 




50 


59.46 


20 37.23 




94 


02.01 


110 54.37 




57 


59.45 


22 54.07 




95 


02.06 


3 5.84 




58 


59.44 


26 26.30 




90 


02.08 


5 2.13 




59 


59.44 


27 45.48 




97 


02.11 


7 19.22 




00 


59.43 


31 50.50 


21 


98 


02.13 


9 25.78 




01 


59. 42 


35 28.98 




99 


61.35 


12 34.00 




62 


59.41 


36 51.84 




100 


00.59 


15 38.45 




63 


59.40 


38 57.98 




101 


00.52 


15 .55.19 


13 


64 


59.39 


41 29.75 




102 


60.25 


17 0. 02 


14 


05 


55.16 


45 23.40 




103 


59.44 


20 14.13 


15 


00 


55.37 


48 47.84 




104 


.59. 08 


21 43.13 


10 


67 


.55.52 


51 49.75 




105 


58.05 


23 28.25 




68 


55.58 


53 55.10 


22 


106 


57.63 


27 33.80 




69 


55.07 


57 3. 65 




107 


57.51 


29 24.64 




70 


55.73 


59 9. 41 


23 


108 


57.45 


30 22.43 




71 


55.85 


109 2 59.82 




109 


57.60 


32 36.99 




72 


55.87 


3 42.46 




110 


57.75 


34 42.90 


17 


73 


55.92 


5 18.23 


24 


111 


57.83 


35 59.32 




74 


57,17 


7 41.72 




112 


58.15 


37 40.68 




75 


59. 04 


11 10.56 




113 


58.88 


41 31.98 




70 


0(1. 37 


13 49.17 




114 


59.11 


42 47.35 


19 


77 


61.51 


10 0.95 




115 


59.48 


44 42.58 




78 


61.53 


17 15.36 




116 


50.94 


47 8.71 




79 


01.58 


21 1.88 




117 


CO. 43 


49 45.47 




80 


01.02 


23 58.88 


26 


118 


60.05 


50 56.03 




81 


01.63 


24 49.13 




119 


58.57 


54 10.58 


20 


82 


01.65 


25 57.08 




120 


57. 57 


55 44.08 




83 


01.00 


27 7. 84 






57.13 


50 24.78 




84 


01.70 


30 57.13 


27 


122 


57.03 


56 34.49 




85 


01.72 


33 27.82 




123 


50.81 


57 47.12 




80 


61.75 


36 15.94 




124 


56.46 


59 43.02 




87 


01.80 


40 15.26 




125 


50.11 


HI 1 39.05 




88 


61.84 


44 28.18 




126 


55.00 


4 25.68 




89 


61.88 


40 39.20 


28 


127 


55.58 


4 34. 45 




-Ji 


61.91 


49 10.17 











UNITED STATES AND MEXICAN BOUNnARY. 



Mean luliUidcs, loiii/itudes, and azinuilim alomj tin 



55 

Colorado 



Monnnients. 


Mean latitude. 


Longitude. 




Azimuths. 




To 
monu- 
inrat. 


Distance. . 
Jfelert:. 


Old No. 


^7 




Back. 








^ 




-. 


^ 




u 




, 




27 


127 


31 


19 


55.5 


111 


4 34.4 


110 


40 12 


290 38 


22 


129 


6,031.5 


XVIII 


129 


31 


21 


4.6 


111 


8 7.8 


110 


34 51 


290 25 


59 


136 


28,973.8 


XVII 


136 


31 


26 


34.2 


111 


25 15.1 


110 


26 12 


290 24 


53 


137 


4,235.7 


XVI 


137 


31 


27 


22.2 


HI 


27 45.4 


no 


21 20 


290 19 


53 


141 


14,746.5 


XV 


141 


31 


30 


8.9 


111 


30 29.1 


no 


20 49 


290 12 


17 


140 


27,505.0 


XIV 


146 


31 


35 


19.1 


111 


52 49.4 


110 


14 37 


2911 8 


20 


150 


19,875.1 


xm 


150 


31 


39 


1.8 


112 


4 37.2 


no 


5 18 


2S9 50 


44 


160 


46,562.1 


XII 


160 


31 


47 


38.1 


112 


32 19.5 


109 


51 13 


2K9 48 


50 


102 


7,273.3 


X 


162 


31 


48 


58.2 


112 


.30 39.0 


109 


48 22 


289 41 


110 


108 


23,415.2 


IX 


168 


31 


53 


15.0 


112 


50 37.9 


109 


39 14 


289 29 


20 


175 


31, 314. 


VI 


175 


31 


58 


55.6 


113 


9 21.2 


110 


24 22 


289 32 


23 


204 


162,894.5 


II 


204 


32 


29 


2.2 


114 


40 48.6 


108 


40 37 


288 39 


38 


205 


3,000.0 




205 


32 


29 


33.4 


114 


48 37.5 










127 


375,887.3 





Mean hitilndcs, lomjitudts, and azimnths along the California live from Monument Xo. 30G to Monument No.SoSon Paciji: 



Monuments. 


Mean 


latimdc. 


Longitude. 


Azim 
Forward. 


uths. 
Ba 


k. 


To 




Old No. 


r 








o 


, ,r 


r . .. 


o , „ 





, „ 




Meters. 




206 


32 


43 5.0 


114 43 23.2 


85 ^ 31 9 


265 


30 52 


207 


809.4 


VI 


207 


32 


43 3.0 


114 43 54.3 


85 30 52 


260 


43 


220 


70, 109. 


V 


220 


32 


39 57.0 


115 28 36.7 


85 i 17 


205 


1 20 


221 


2,780.4 


IV 


221 


32 


39 49.2 


115 30 23.0 


85 11 33 


264 


15 15 


252 


132, 080. 3 


HI 


252 


32 


33 8.0 


116 54 20.4 


84 17 57 


264 


14 51 


254 


9, 068. 




254 


32 


32 38.0 


117 12.2 


84 14 43 


204 


13 32 


255 


2,466.0 




255 


32 


32 30.6 


117 1 46.2 


84 14 34 


204 


12 53 


256 


4, 941. 2 


' 


256 
258 


32 
32 


32 14.4 
31 111 


117 4 .-.4.6 


84 12 57 


264 


n 32 


258 
206 


4,125.3 


226, 379. 6 



The foregoiug report is hereby attested by tlie signatures of all the mt'iiibers of the Interna- 
tional l>ouiidary Commission. 

Done at the office of the commission in the city of Washington, 1). V., this the 14th day of 
Augnst, 1896. 



Jacobo Blanco , 

Iiujeniero en Jefe de la Secciihi Me.vicana. 
Valentin Gama, 

Adjtmto Astrimomo. 

GUILLERMO B. Y PlTGA, 

Adjunto Astro iiomo. 



.). W. Barlow, 
Colonel of Engineers, 
Enf/ineer in Chief of the American Section. 

A. T. MOSMAN, 

Assistant, 
United States Coast and Geodetic Survey. 
D. D. Gaillard, 
Captain of Engineers, I'. N. A. 



At a meeting of the International Boundary Commission held at the office of the commission^ 
in Washington, D. C, August 14, 1896, present all members, the following resolutions were 
unanimously adopted : 

1. That the full report of the Joint commission prescribed in Article V of the convention of 
July -29, 1882, shall consist of the accompanying manuscripts, written in the English and Spanish 
languages, both in duplicate, compri-sing, in the English copies, 100 pages, and in the Spanish 
copies, 94 pages, of type-written test, includiug tables. These copies have this day been signed 
by all the members of the commission, and one copy in each language will be retained by each 



56 



UNITED STATES AND MEXICAN BOUNDARY. 



section of the cominissiou for transmittal to the proper department of its government; also, 
copies, each iu duplicate, one for each section of the commission, of the joint map of the survey, 
comprising nineteen engraved sheets, on a scale of 1 -4- 00,000, covering the boundary from the 
Rio Grande to the Pacific Ocean aud showing the topography of a belt of territory 5 miles wide. 

2. The report and map above specified are now complete and have been dnly attested by the 
signatures of all the members of the commission. 

3. In addition to these will soon be completed a set of illustrations, 300 in number, prepared 
from photographs taken iu the field, showing views of the 2r>8 monuments marking the boundary 
and special characteristic scenes. 

4. It is further agreed that the engraved plates and electrotypes of the map, twenty of 
each, shall be equally divided between the two sections of the cominissiou. These plates and 
electrotypes <ire numbered from the llio Grande westward; the United States section will receive 
tlie engraved plates having odd numbers and the electrotypes having even numbers; the Mexican 
section to receive the others, the object being that each section shall have a complete set 
(engraved and electrotype plates) of the entire map. The manuscript drawings of the map will 
also be divided equally, each section retaining the sheets inked by its own draftsmen. 

5. Tiie half-tone plates, prepared from photographs, being in duplicate, each section will 
retain one complete set. These will be completed under the supervision of the engineers in-chief 
and by them forwiirded to their respective governments. 

6. The International Oommission, having no further business to transact, adjourns sine Me. 



Jacobo Blanco, 

Yngo. en •Tefe, See. Me.v.; 
Valentin Gama, 

Adjiinto AxtroHomo ; 
GUTLLERMO B. Y PTTGA, 

Ad/unto A.strt'niomo ; 

Commi.ssioners. 



J. W. Barlow, 
Colonel of Eiiginera, U. S. A., 
Engineer in Chief, American Section; 

A. T. MOSMAN, 
Assinf. U. S. Coast and Geod. Survey ; 
1). U. Gaillard, 
Captain of Engineers, U. S. A., 

Commissioners. 



P^RT II. 

REPORT 

OF THE 

UNITED STATES SECTION 

OF THE 

INTERNATIONAL BOUNDARY COMMISSION, 
UNITED STATES AND MEXICO. 



CX^NTENn^S OY REPOKT (W UNITED STATES SECTION. 



Chapter I : 

Organizatiou aud transportation — Page. 

First meeting of the lutevnational Boundary Commission, at Ciudad Juarez 7 

CJeneral division of the work of the I'nited States section 8 

Ijist of members of commission and employees 8 

List of wagons, mules, horses, etc 8 

Tentage 8 

Quartermaster, surgeon, and military escort 8-9 

Xlenibi IS of— 

(1) Astronomical party 9 

(2) Tangent party 9 

(3) Topographical party 9 

Photographic outfit 10 

Field telegraph line , - 10 

Monument erectiou party U 

(1) Survey party for tangent work and topography from the Colorado River to the Pacific Ocean 11 

(2) Survey party for operations east of the Colorado to the one hundred and eleventh meridian 12 

Monument erection party on — 

Parallel 31- 20' 12 

Sonora line 12-13 

California line -. 13 

Office force employed in San Diego 13 

Escorts of U. S. troops serving with commission. List of officers and number of men 14 

Chapter II : 

General description of the country adjacent to the international boundary line- 
Rainfall, rivers, springs, ami wells 15 

Vegetation, mountain ranges, settlements 15 

Mining and stock-raising, deserts 15-10 

Section I, parallel 31^ 47' 16 

Section 1 1, the meridian section 17 

Section III, parallel 31^ 20' - 17-20 

Section IV, tlie azimuth line, from the west end of parallel 31° 20' to the Colorado River 20-26 

Section V, Colorado River 26-27 

Section VI, azimuth line, from the Colorado TJi ver to the Pacific Ocean 27-29 

Water supply to working parties on the deserts 30 

Mirage 30 

Reconnaissances 30-31 

Chapter III : 
Astronomy — 

Instruments and outfit 31 

Description of observatory tent and mounting of the astronomical instruments 32 

Longitudes 33 

Results for longitude 33-35 

Latitudes 35 

Azimuths ■- 3i) 

Astronomical observer, computer, and recorder 36 

Introduction to Star Catalogue, by Prof. T. H. Safford 36-37 

Introduction to the revision of Star Catalogue, by Prof. T. H. Satt'ord 37 

Mean declinations of 621 latitude stars 38-48 

Authorities for star catalogue, by Prof. T. H. Safford 48-62 

Report of John F. Hayford, assistant astronomer, with observations aud results for latitude and 

azimuth at fifteen stations along the boundary 62 

Time expended at the first twelve stations 63 

Description of instruments and methods used in the determination of azimuths 64 

Example of observation and computation of azimuth 65-68 

Formulie useil in reduction of azimuth observations 66-67 

2 



UNITED STATES AND MEXICAN BOUNDAKY. 3 

Chapter III— Continued. 
Astronomy — Continued. 

Azimuth determinations, summary Page. 

Discussion of results for azimuth ^^~^^ 

Value of micrometer of theodolite No 725 ' 71-72 

Latitude determinaticms ...'!".!!"."!!!". '^^"'^^ 

De.scription of instruments used and stars observed "^^'l^ 

Latitude determinations — ^^ 

Station No. 1 

Station No. 2 [\ H-7ii 

Station No. 3 ......"... ''*' 

Station No. 4 '^^ 

Station No. 5 '. '^^-^ 

Station No. 6 " '^-'^^ 

Station No. 7 ....'. 82-83 

Station No. 8 8*-85 

Station No. 9 **6-87 

StatiouNo.lO **8-89 

Station No. 11 ,. 90-91 

Station No. 12 ;."";; 92-93 

Station No. 13 ' 94-95 

Station No. 14 ' 96-97 

Station No. 15 ....'..".!.. "'^ 

Summary of micrometer determinations 99-100 

Discussion of results for latitude no ^^^ 

Triangulation 103-108 

Plate 1.— Sketch ..f triangulation near El Paso, Tex ^^'inq 

Plate 2.— Sketch of triangulation near Nogales, Ariz ]?\ 

Plate 3.— Sketch of triangulation near Yuma, Ariz ".'..... ! 

Magnetic observations ^^^ 

Chapter IV : 
Geodesy- 
Geodetic operations 

Constants used ^ 

Deduitiou of "straight line" ^^^ 

Number of straight lines that eau be run between Vwopoini.s on 'the earth's suifaco ng 

Methods and instruments used. 

Parallel 31^47' '.'..""'..]]'..'. ^" 

Back azimuth on parallel 31 47' , 

Computation of oltsets from the tangents jj'? 

Sketch showing oft'sets ^'^ 

Locating the monument sites, the meridian section ,,c 

Parallel 31 20' ^^* 

Back azimuth errors ou p.irallel 'M L'O 118-119 

The Sonora azimuth line ^^^ 

Table of offsets fr.uu the tluoretical straight' line joining M;,numVntsNos."i27"and204 ' "^'m 

The California azimuth lino " 

Geueral remarks on tangent and line work ....i.i... i" 12^-19^ 

Triangulation in the vicinity of i:\ Paso, Tex ] ]Z. 

Gecgiaidiie.il position.s of points in the vicinity of El Paso Tex 19- 

■'■"•""lii'l'il at San Pedro Kiver ;.. 'Z 

TriannulatiMu;,! Nogales, Ariz i!. '.'."." .'.'.'.".'.'.' yyn 

Geograpli i, al jiositions of points in the vicinity of Nogales, Ariz i ! 197 

Triangulation iu the vicinity of Yuma, Ariz ' .' j7,^ 

Geographical positions of points in the vicinity of Yuma, Ariz 19g 

Appendix No. l.-Rcport of Mr. E. L. Ingram, assistant engineer, on tangent aiuilinewo'rki.';.' 128-133 

Appendix No. ..-Report of Mr. E. L. Ingram, assistant engineer, on monument location and erection 

on parallel 31 4/', mendiau section, and California azimutli line 133-139 

Appendix No 3.--Report of Mr. B. A. Wood, assistant engineer, on monument location 'andcrection on ' 

l)arallel 31^ 20 and the Sonora azimuth line 110-144 

Appendix No 4.--Report of Mr. .John F. Hayford, assistant a^trouom'erVonVinc'determinaiiouY.etwJen 

the Colorado River and Nogales, Ariz ^^- ,g„ 

Chai'TKR V: 

Topography — 

Methods used iu measuring distances 153-154 

Table of distances along parallel 31^ 47' determined by tria'ngulatlon^ stadia,' and chain I.54 

Methods used in contouring and " lilling iu " jgg 

Area included in topographic belt; average number of locations per square mile; nuniberof miles run. 155-156 



4 UNITED STATES AND MEXICAN BOUNDARY. 

Cii.vi'TEii V — Coiitimnil. 

Topography — Con tinned. Page. 

Table showing discrepancy between measured and compiiti'd distances alou;; the boundary I.i6 

Renioasurements - 1.56-157 

Tables of mean error in closing per kilometer 157-158 

Table of error iu elevation in closing per kilometer 159 

Average length of courses KiO 

Line of levels ItiO 

Table of elevations of tops of masonry bases of monuments above mean sea level lt)l-164 

Magnetic declination 165 

Atmospheric vibration 166 

Appendix. — Report of .Mr. .1. L. \an druum, assistant engineer 166-173 

ChaI'TF.r VI : 

Old monuments — 

Description of the old monunients founil, with their inscriptions 173 

The initial monument on I'acilic- coast 173 

The five iron monuments on California azimuth line 174 

Monuments found on Souora azimuth line 174 

No. 1 1, of iron 174 

Others, rude heaps of stone 174-175 

Monuments marking the boundary along parallel 3^ 47'. the meridian section, and parallel 31' 20' 175 

Initial monument near the Rio Grande (cut stone) 175 

Monuments Nos. 2 and 3, on parallel 31' 47' 175 

Monuments Nos. 4, 5, 6, and 7, on parallel 31>^ 47' 176 

Monuments Nos. 8. 9, and 10, on the meridian section 176 

Monuments Nos. 12 to 27, on parallell 31° 20' 176-177 

Monument No. 26, at Nogales, Ariz 177 

Letter from commission to Secretary of State on proposed reservation alimg bouudary 178 

.Monumeut 27, western! of parallel 3L 20' 178 

CUAPTEU VII: 

New monuments — 

Provisions of the conventions of 1882 and 1889 179 

Description of all the new monuments erected; their location; kind of monument, whether stone or 

iron, and the inscriptions placed ou them 179-180 

Description of the irou monuments 179-180 

1. I'ar.allel 31^ 47' and meridian section, Monuments Nos. 1, 2, 3 180-181 

Inscriptions of plates for stone monuments 181 

Ditfereuces in United States and Mexican otfsets, locating monuments, Monument No. 4 181 

Method of constructing the concrete base and erecting iron monuments 181 

Monuments Nos. 5 to 15 182 

Ditticulties from lack of water in desert 182 

Monuments Nos. 16 to 39— Monument No. 40, at "corner"— silver-mining region 183 

Monuments Nos. 41 to 52 — Annoyances encountercjl on meridian section 184 

Organization of party 185 

2. Parallel 31^ 20' 185 

Monuments erected from Nogales eastward 185 

Much rain encountered, Monuments Nos. 53 to 66 186 

Apache outlaws, Monuments Nos. 67 to 80 187 

Guadalupe Canon 187 

Monuments Nos. 81 to 121 188-189 

Monument No. 122, at Nogales 189 

Monuments Nos. 123 to 127 • 190 

3. Souora azimuth line 190 

Difficult work iu the Pajaritos, Monuments Nos. 128, 129 190 

Monumeut No. 152, on Lesna Mountain, Monuments Nos. 130 to 158 191 

The Tule and Tinajas Altas Mountains, Monuments Nos. 159 to 205 192-193 

Monument No. 204, Colorado Valley 193 

Organization of party 194 

Colorado River section of boundary 194 

4. California azimuth line, Monuments Nos. 206 to 210 194 

Monument No. 210, iu sand hills 194 

Monument No. 223, below sea level, Monuments Nos. 211 to 231 195 

Proposed irrigating caual 195 

Monument No. 231, on crest of coast range overlooking desert 195 

Monuments Nos. 232 to 252 — Monuments Nos. 246 and 247, on crest of Tecate Mountain 196 



UNITED STATES AND MEXICAN BOUNDARY. 5 

t'HAi'TKi! VII — Coutiuui'd. 

New moiiumeuts — Continued. p 

Destruction and reerection of Monument No. 255, Monuments Xos. 253 to 25S I97 

Inscription on Monument No. 258, documents placed in foundation Xi)>5 

Summary lyi) 

Plate 4. — Design for iron monuments Ki;) 

Plate 5.— Designs for sectional iron monuments l;)!) 

Plate 6. — Design for stone monuments njij 

C'HAI'TEK VIII: 

Photography, biology, and financial statement^ — 

Photographers employed at different times liiy 

Description of photographic instruments 1!)<I 

Photographs of old and new monuments 200 

Half-tone engravings 200 

List of half-tone jilatcs 200-201 

Biological work 204 

Work of Dr. E. A. Mearns 205 

Work of Mr. V. X. Holzuer 205 

Dr. E. A. Mearus's report 205 

Financial statement 206 

Cost of the field work 206 

Tlic different items 206 

Tables showing cost of services, subsistence, transportation, etc 207 

Cost of water 207 

Cost of preparing the reports, including maps, illustrations, etc 208 

Chapter IX: 

Description of maps, profiles, and plates — 

Map of boundary line (18 sheets) from the Rio Grande to the Pacific, 1 — 60,000 208 

Sheet No. 19, Colorado River, 1-^60,000 208 

Profile of boundary line (5 slieets), 1 — 60,000 208 

Index map of the boundary (2 slieets), 1 -f- 600,000 208 

Authorities used in compiling index m:ip _ 208 

Copperplates and electrotypes 208-209 

Chai'i i;k X. — Appendix : 

Report of Asst. Prof. L. .S. Smith on 1 aiises of error in stadia measurement — An experimental study of 
field methods which will insure to stadia measurements greatly increased accuracy — 

I. Introduction 209 

II. Study of atmo.spheric unsteadiness 210 

(a) Method of work 210 

(b) Lateral vibration 211 

(c) Vertical vibration 211 

(d) Vibration causes only accidental errors 212 

(e) Typical curves 212-219 

III. The study of differential refraction — 

(a) Relation between unsteadiness and refraction 218-220 

(u) Probable explanation 220-221 

(c) Experimental evidence of dift'erential refraction 221-224 

(d) Effect of length of sight and hour of day on refraction 225 

Table No. 2. — Record of experiments on stadia measurement 225 

Tables of results of experimouts 225-227 

Summation of results 229 

(e) Effect of refraction on aci-umulating errors 229 

IV. The proper remedy for systematic errors — 

(a) The correct statement of the problem 230 

(6) The case applied to the recent survey of St. Louis, Mo 231 

(c) The accurate way of determining the interval 231-233 

Interval determination of Brandis transit 1.584 233-234 

Interval d<'termination of other transits 233 

Table 4. — Comparison of results of measures by st.adia on meridian section and parallel 31"^ 20' 

with those by triangulation 235 

Generalization drawn from data given 23() 

Tal)le of results 237 

(d) Experimental work showing compensation of errors 238 

V. .Summary of conclusions 239 

Kind of rods to use 240 



UNITED STATES AND MEXICAN BOUNDARY. 



LIST OF ILLUSTRATIONS. PART IL 



1. Parish Chmcli, .Tniiicz 7 

2. San Bcinaitliiio Springs, Ariz 11 

3. Turkey Canon, Ariz 15 

4. Mosquito Springs, N. Mex 17 

5. Camp at Dog Springs, N. Mex 17 

6. Camp near San Bernardino 18 

7. Cu.stoiu-house, La Morita 19 

8. Mexican custom-house, Nogales 20 

9. International si reet, Nogales 2(» 

10. Sonoy ta River, Sonora 23 

11. Giant cactus 23 

12. Trail to Monument No. 184 24 

13. Tinajas Altas, Ariz 25 

14. Astronomical Tent, Tijuana 32 

15. Nogales looking northeast 120 

16. Camp near Lech ngii ilia Mountains 172 

17. Old monument on Pacific Coast 173 

18. Old Monument No. II 174 

19. Old Monument No. XII 175 

20. Old Monument No. XVI 175 

21. Old monument south end of meridian section 176 

22. Old Monument Arizona and New Mexico 177 

23. Old Monument No. 26, Nogales 178 

24. Rebuilding Monument No. 40 186 

25. Old Monument No. 18, San Bernardino 187 

26. Camp of monument party at Bisbec, .Vriz 188 

27. Main camp at La Noria, Ariz 180 

28. Erection of Monument No. 153, La Lesna 191 

29. New Monument No. 184 102 

30. Hot Springs, Tijuana 106 

31. New Monument No. 2.55 197 

32. New Monument No. 258 198 

33. Barranca Verde Ranch, California 205 



REPORT OF THE UNITED STATES SECTION 
OF THE COMMISSION. 



CHAPTER 1. 

ORGANIZATION AND TRANSPORTATION. 

ruder the provisions of the conveution of July 29, 1882, revived by that of February 18, 1889, 
between the United States and Mexico, providing for an international boundary survey to relocate 
the existing frontier line between the two countries west of the Eio Clrande, the President of the 
United States directed the appointment of Lieut. Col. J. W. Barlow, Corps of Engineers; First 
Lieut. D. D. Caillard, Corps of Engineers; and Mr. A. T. Mosman, assistant, United States Coast 
and Geodetic Survey, members of a (commission, who, with corresponding appointees of the 
Mexican Government, would form an International Boundary Commission to carry into effect 
the provisions of those conventions. 

These oflflcers were notified of their appointment early in November, 1891, and were directed 
to proceed to El Paso, Tex., for consultation with the INIexican members who were expected to 
reach that point on the 7th of the month. 

Lieutenant-Colonel Barlow and Mr. Mosman were instructed to visit Washington for 
conference with the Secretary of State befofe proceeding to El Paso, at whicli place they arrived 
on the 14th; Lieutenant Gaillard having preceded them by a few days. 

Sefior Don Jacobo Blanco, engineer in chief, and Senores Felipe Valle and Jose Tamborrel, 
associate engineers, appointees on the i>art of Mexico, were already on the ground; and after the 
usual official and personal civilities had been observed, a meeting of all the members was held at 
the Mexican custom-house in .Juarez on the 17th of November, 1891, when the International 
Boundary Commission was duly installed. 

Tlie proceedings at this meeting were somewhat formal in character, and resulted in the 
preparation and signing of a document declaring the fact of the organization of the commission; 
copies in both English and Spanish were then made and transmitted to the proper departments 
in Washington and Mexico. 

The preparaition of a plan of operations was now given careful consideration by the two 
engineers in chiel' with the assistance of the associate engineers, and was adopted on the 21st of 
the month. Its provisions related entirely to the methods to be pursued in making the surveys. 
A copy of this agreement will be found in the report of the joint commission. 

The Mexican section of the commission at this time was prepared to take the field in prose- 
cution of their surveys, having already been provided with instruments, camp equipage^ and an 
escort of troops. The American commission, on the contrary, had nmde no provision whatever, 
and there being no further duty to be performed by them until the necessary men and material 
conld be assembled for field operations, the joint commission separated on the 22d of November, 
the Mexicans to begin their survey, the Americans returning to the Eastern States to procure 
instruments and skilled assistants, preparatory to entering upon their part of the required work. 

The months of December, 1891, and January, 1892, were spent by the American commissioners 
in procuring instruments, engaging assistant engineers and other necessary employees, considering 
and devising plans for organizing the field parties and supplying them while engaged in the desert 
and mountain legions to be crossed during the progress of the work. 



8 UNITED STATES AND MEXICAN BOUNDARY. 

The American members reassembled at El Paso on February 2, 1892, aud at ouce begau the 
work of organizing the field parties and collecting the necessary transportation. 

A general division of the work of the commission was decided upon, as follows : The senior 
commissioner, who, by designation of the President of the United States, was also the disbursing 
officer, to have charge, as engineer in chief, of all duty pertaining to the location, construction, 
and erection of monuments; the disbursement of the funds, including the payment of employees 
and purchase of property aud supplies. The second member to have general supervision over the 
running of the line in the field and the topography. The third commissioner to have general 
charge of the astronomical work. This division of labor was substantially adhered to throughout 
the continuance of operations. 

Following is the organization of the American commission on taking the field at El Paso in 
February, 1892 : 

J. W. Barlow, lieutenant-colonel of Engineers, commissioner, and engineer in chief; D. 1). 
Gaillard, first lieutenant of Engineers, commissioner; A. T. Mosmaii, assistant, Coast and 
Geodetic Survey, commissioner; L. Seward Terry, secretary and disbursing clerk; J. F. Hayford, 
assistant astronomer; J. L. Van Ornum, assistant engineer and topographer; E. L. Ingram, 
assistant engineer; B. A. Wood, assistant engineer; T. H. Logan, transportation clerk; J. T. 
Amos, field clerk; James Page, computer; P. 1). Cunin'ngham, levelman; J. H. Wright, photog- 
rapher; L. S. Smith, transitmau; A. F. Woolley, jr., transitmau; H. B. Finley, recorder; N. G. 
Ellerbe, recorder; Thomas Evans, rodman; Joe H. AVheeler, rodman; D. L. Ledbetter, rodman; 
C. W. Speiermann, rodman; Henry Griilin, rodman; Edmund Davis, rodman; A.J.Sampson, 
rodman; A. Van Ornum, chaiuman; W. T. Simpson, chainman; Luke O'Reilly, targetman; F. (x. 
Malloy, targetman; Albert Lang, targetman; E. Frye, targetman; J. S. Bilby, carpenter; W. J. 
Tucker, blacksmith; L. C. Chriss, wagon master (temporary); James Groves, chief packer. 

Besides these, about twenty men were employed as teamsters, packers, cooks, and hel[>ers; 
the aggregate number of employees of all classes being about sixty. 

In addition to the above, Capt. W. L. Finley, ^STinth United States Cavalry, was detailed by 
the War Department to act as quartermaster and commissary of subsistence for the commission ; 
and Capt. and Asst. Surg. E. A. Mearns, United States Army, as medical officer. 

By an arrangement with the Superintendent of the United States Coast and Geodetic Survey, 
a longitude party, consisting of C. II. Sinclair and G. li. Putnam, observers, audO. B. French, 
recorder, was detailed to determine the longitude, by telegraph from Los Angeles, of San Diego, 
Yuma, Nogales, and El Paso. A point on the boundary 100 miles west of El Paso was also 
included in the work of this party. 

The personnel of the organization was not entirely permanent; some changes among the 
subordinates of the engineering force occurred from time to time as contingencies arose; while 
among the teamsters, cooks, and laborers, the changes were quite frequent. In the higher 
departments the men employed continued, without exception, until the close of the work for which 
they were engaged. 

The transportation and camp equipage was purchased for the expedition, and proved to be 
of excellent quality, well adapted to the service required. It was at first as follows: 7 four-mule 
baggage wagons, 3 six-mule water-tank wagons, 3 two-nuile light spring wagons, 1 two-mule 
buckboard, 1 four-mule ambulance, 25 mules for packing, 83 mules in all, and 11 saddle ponies. 

Tiio tentage consisted of 5 otTficers' wall tents, 12 conical wall tents, 20 small wall tents. 

It was found unnecessary to materially increase the number of animals during the entire 
progress of operations; but experience taught us that a special pack train was a very expensive 
method of transportation, and not an absolute necessity. In May, 1892, another baggage 
wagon was purchased, and in the following October the pack train was greatly reduced, and 
later on discontinued; the animals being put in harness and employed in hauling additional 
wagons, which were much needed. These animals were, however, frequently used for packing on 
parts of the line where wagons could not be taken, and restored to the teams when the emergency 
had passed. 

Captain Finley served but a short time with the commission. His services were valuable and 
appreciated in procuring and organizing the transportation, but after a few days of camp exjierience 



UNITED STATES AND MEXICAN BOUNDARY. 9 

the Captaiu, at bis own request, was relieved ou the 25th of March, 1892, and his duties transferred 
to Maj. T. H. Logan, formerly of the Fifth United States Infantry, who ably and zealously performed 
them for a period of twenty mouths, when physical incapacity — the result of an old wound — 
compelled his resignation. 

Assistant Surgeon Mearns continued with the surveying expedition, being a most efficient and 
careful medical officer, as well as an enthusiastic and energetic collector of specimens of natural 
history, until relieved by request of the medical department, in jSTovember, 1892. Dr. Mearns was 
restored to the commission in July following, and r.emained until the close of its field work in 
September, 1894. On leaving the field Dr. Mearns was assigned to professional duty at Fort 
Myer, Va., and, with the permission of the War Department, continued the preparation of his 
biological report with his usual zeal and industry. 

The commission, on commencing operations at El Paso, was provided, by direction of the War 
Department, with a military escort to accompany the expedition as a protection against Indians 
or other marauders. This force consisted of 20 enlisted men of the Tenth Cavalry, Lieuts. P. K. 
Trippe and 11. G. Paxtou commanding, and a detachment of 30 enlisted men of the Twenty-fourth 
Infantry, under Lieut. A. (3. Ducat, jr. The latter officer was relieved at his own request before 
taking the field, the detachment going out under the command of Lieut. J. K. Seyburn, Twenty- 
fourth lufantry, who was also the acting quartermaster and commissary of subsistence for the 
escort. 

Many changes occurred in the personnel of the escort, the troops being relieved and others 
substituted as the exigencies of the military service required. A complete list of the several 
officers and detachments serving with the commission will be given in another place. 

The commissioners are pleased to express their appreciation of the assistance rendered by the 
several officers who served with the escorts, and of the high soldierly qualities displayed by them 
in many difficult and laborious situations. They would also testify to the general good conduct 
of the enlisted men, and their usual cheerful performance of duty. 

During the first season's opei-ations it was deemed advisable to keep the entire organization 
as nearly iutact as possible, and under the constant personal supervision of the commissioners. 
It was also expected to work in concert with the Mexican expedition, and possibly on alternate 
sections of the line, which would have greatly lessened the labors of each party. Owing, however, 
to various causes, among which was the fact that the Americans were able, with their better 
organization and more practical methods, to make more rapid progress than the Mexicans, this 
plan could not be carried out, and it was finally determined that both parties should run the 
entire line, each selecting such points for astronomical determinations as might be thought proper, 
and afterwards compare the results. Under all the existing conditions this was the only practical 
method of proceeding. 

To carry out the work of the American commission conveniently the whole force was sub- 
divided into detachments as follows, the general camp moving as often as 7iecessary to keep within 
touch of all sections : 

1. Astronomical party for determining latitude and azimuth: J. I'\ Ilayford, assistant astron- 
omer and observer; James Page, computer; H. B. Finley, recorder; J. S. Bilby, general helper; 
a cook and 2 teamsters; 1 spring wagon, 1 baggage wagon, and, when necessary, 1 water-tank 
wagon. 

2. Tangent party for runniug the tangents: E. L. Ingram, assistant engineer and observer, in 
charge; N. G, Ellerbe, recorder (temporary); 2 chain men; 4 target men; 1 cook and 1 helper; 2 
teamsters; 1 spring wagon, 1 baggage wagon, and 1 water- tank wagon. 

3. Topographical party: J. L. van Ornum, assistant engineer, in charge: P. D. Cunningham, 
level man; L. S. Smith, transit man; A. F. Woolley, jr., transit man; fi rod men; 1 cook and 
1 helper; 3 teamsters. 

The main supply camp, with the commissioners and field office, frequently included one or 
more of the other jiarties, and for convenience and economy combined the messing outfits. This 
was especially so in the beginning. Afterwards it was found expedient to separate the parties 
more completely. 

Besides the parties above enumerated there were employed with the supply camp: B. A. 
Wood, assistant engineer, draftsman; T. H. Logan, quartermaster and commissary; J. T. Amos, 
S. Doc. 217^5 



10 UNITED STATES AND MEXICAN BOUNDARY. 

field clerk and assistant ; J. H. Wright, photogi-aplier; 1 blacksmith. 1 wheelriglit and carpenter, 
1 cook and 1 helper, several teamsters and laborers. 

Of the cooks and teamsters but few remained permanently, and it was only after numerous 
trials and changes that a satisfactory complement of these indispensable employees could be 
obtained. A plan which worked very well was finally adopted with the teamsters of giving a 
monthly increase of wages for satisfactory and continuous service. 

The photographic work was first undertaken by J. II. Wright. He was soon found to be ill 
ada])ted to field service, and his place was supplied by M. .J. Lemnion for a short period. He was 
also unsatisfactory, and Mr. I). R. Tayne was employed iu August, 1892, and continued to the 
close of the entire work, rendering most faithful and efficient service in his profession as photog- 
rapher, and also as overseer in the erection of monuments. 

In conducting the survey across the desert west of the Kio Grande the expedition encountered 
severe difficulties. The absence of water iu the vicinity of the line for the first 50 miles, and the 
soft, sandy nature of the soil, which retarded the progress of wagons, being among the most 
serious. Men and animals were new and unseasoned to hardship, but in a few days the majority 
became accustomed to field life, and the work soon progressed rapidly and satisfactorily. 

The main camp and supply train reached Old Monument No. 4, 50 miles west of the Rio 
Grande, on the 20th of March, 1892. To this point all supplies were hauled across the desert 
from El Paso. After leaving the vicinity of the river, water was obtained from Strauss and Lanark, 
stations on the Southern Pacific Railway, by hauling from 10 to 15 miles. 

While camped at Old Monument No. 4, and its vicinity, water was obtained from a well 3 miles 
north of this monument. This well is 100 feet deep, the water raised by windmill and horsepower 
for supplying a large herd of cattle owned by a ^Irs. Wragg. The quantity was quite abundant 
but the quality bad, being strongly alkaline. Beyond, in New Mexico and southeastern Arizona, 
water was obtained with less difficulty, several natural springs and a number of ranchmen's wells 
having been found available. 

From this point (Monument No. 4) westward advantage was taken of the Southern Pacific 
Railway in the transportation of supplies from the most convenient point of purchase to the 
stations nearest the field of operations, which method greatly relieved the strain upon the animals 
of the expedition. 

The survey continued without serious inconvenience, reaching the "corner" at the western 
extremity of the boundary on parallel 31° 47' iu the latter part of April. The main camj) remained 
here from the 22d of April until the 18th of May. At the latter date the astronomical observa- 
tions had been completed, including an exchange of telegraphic signals between this station and 
El Paso. 

For the latter puri)ose a field telegrai)h line was erected to this point from the railroad at 
Separ, about 35 miles distant. The material for the line was loaned by authority of Gen. A. W. 
Greeley, Chief of the Signal Service of the War Department, and put up under the direction of 
Lieut. Frank Greene, United States Signal Service, by a company of the Twenty-fourth United 
States Infantry, Bvt. Maj. James N. Morgan, commanding. The wagon transportation was 
supplied from the boundary train. This work was performed with remarkable expedition. The 
line was in working order on the evening of the fifth day after the material arrived. It was used 
four nights for excihauge of signals, and immediately removed. 

Before moving this camp the tangent and topographical parties carried their work well along 
the meridian southward, and were able to obtain water from Mosquito Springs, 15 miles distant 
and near the line, on the Mexican side. The water in the vicinity of camp at the "corner" was 
scarce and of poor quality, a moderate supply being obtained from a well owned by Mr. Boyle, 
3 miles west of camp. 

From the wells of Mr. Rector, several miles south, some water was obtained, and also from 
the Garrizalillo Springs, 15 miles eastward. Wood in abundance and of excellent quality was 
always available, being generally the roots of dead mesquite, which were obtained with little labor 
and made the best of fuel for cooking. For evening campfires grease wood, yucca, and the 
branches and roots of mesquite served a good purpose. 

For a time a supply station was established on the railroad at Separ, whence stores were 
liauled by the commission teams to the camps along the parallel of 31° 20' as far as San Bernardino, 



UNITED STATES AND MEXICAN BOUNDARY. 1 1 

some miles west of tbe Guadalupe Mountains. From the latter point, until within reach of 
Nogales, a supply station was established near Bisbee, on the Arizona and Southeastern Railroad, 
which point was easily accessible by the wagons of the expedition for a distance of 100 miles along 
the boundary. 

The main camp reached San Bernardino on the 26th of July, and all the work of the survey 
was completed in that vicinity during the month of August. 

On August C a detachment of men and teams, under T. H. Logan, was sent overland 240 miles 
to El Paso to take up the work of monument ei'ectiou on the parallel of 31^ 47'. 

This transportation consisted of 4 baggage wagons, 1 water-tank wagon, 1 spring wagon, 
1 buckboard, and 2 saddle ponies. At El Paso another spring wagon with 2 horses was purchased 
for this party, and later on a water-tank wagon and 1 baggage wagon were added, the animals 
being supplied from the 1.5 pack mules which had been sent from the main camp for duty with the 
monument party. 

This party when fully organized consisted of the following men and transportation: One com- 
missioner, Lieut. Col. J. W. Barlow, in general charge; E. L. Ingram, assistant engineer, in charge 
of location party; T. H. Logan, quartermaster, and in charge of working party; D. R. Payne, 
photographer and general assistant; 1 stone mason, 1 blacksmith, 1 rodman, 7 teamsters, 4 laborers, 
1 cook, and 2 helpers — a total of 21 persons. 

A Mexican party, consisting of one commissioner, an assistant engineer with helpers, and 
appropriate transportation, accompanied this party and assisted in the location of monuments. 
The work of construction and erection was done wholly by the American section. 

A detachment of 12 enlisted men from the Twenty-fourth Infantry and 2 troopers from the 
First Cavalry were attached as an escort for this party, and were provided with a baggage wagon 
and 4 mules for transportation. 

This monument party continued work until the close of November, erecting monuments along 
the parallel of 31° 47' and the meridian section to the parallel of 31° 20'. It then moved overland 
and joined the main survey camp near La Noria, Ariz. 

The entire force was now engaged in completing the survey of the line along parallel 31° 20' 
to the angle at the one hundred and eleventh meridian, where the boundary changes its direction. 

The weather in this elevated mountain region having become very trying upon the men in the 
field, and it being very important that the desert country adjoining the Colorado River be surveyed 
before the heat of summer should make that work impracticable, it was decided to transfer the 
entire expedition to Yuma and carry on the survey from the Colorado River across the deserts on 
either side during the winter and early spring months. 

The expense of shipping by rail was found to be so great that it was decided to move over- 
land, and to accomplish this with the least possible delay in prosecuting the fleldwork, the trans- 
portation was divided. About one-half was started via Tucson and along the wagon road near 
the Southern Pacific Railway on the lath of December, 1892. This detachment Safely reached 
Yuma on the 31st of the month. The other half remained with the parties which were completing 
the survey in the vicinity of Nogales and followed early in January, 1893. 

The engineers and others engaged upon the survey, with their instruments and i)ersonal 
baggage, were sent by rail to Yuma, reaching that point in time to commence work at once, with 
the aid of the first section of the transportation previously sent over. 

Two survey parties were here organized from the whole force to push the surveys both east 
and west from the Colorado River, with a view to completing the work on the Yuma and Colorado 
deserts before the advent of hot weather. 

After finishing at Yuma the astronomical determinations for latitude and azimuth, and 
connecting the observatory with old Monument No. VI, on the west side of the river, and old 
Monument No. II, on the east side, by triangulation, the astronomical party was discontinued as 
a separate organization and its menjbers assigned to duty with the two line parties. 

The entire organization was now divided as follows: 

1. Survey party for tangent work and topography from the Colorado to the Pacific: E. L. 
Ingram, assistant engineer in charge, running theodolite; P. D. Cunningham, trausitmau; H. B. 
Fiuley, transitman ; C. W. Spiermann, levelman; A. Lang, in charge of heliotrope; 9 rodmen, 1 
cook and 1 helper, 4 teamsters, 2 packers, and 1 guide— a total of 23 persons. 



12 UNITED STATES AND MEXICAN BOUNDARY. 

The transportation of this party consisted of 2 baggage wagons, :i water-tanlv wagon, a 
light spring wagon, Ki draft mules, and 2 riding horses. 

2. Survey party for operations east of the Colorado to the one hundred and eleventh 
meridian: J. L. Van Ornuin, assistant engineer, in charge of topography; J. Y. Uayford, assistant 
engineer, in charge of the azimuth line; L. S. Smith, transitman; James Page, transitman; Ernst 
Franke, levelman; J. T. Amos, clerk and assistant quartermaster; 3 heliotropers, 9 rodmen, 1 
mechanic, 1 packer, 4 teamsters, 2 cooks, and 3 laborers— a total of 29 persons. 

The transportation for this party consisted of i baggage wagons, 2 water-tank wagons, 2 
spring wagons, C pack and 5 riding animals — a total of 41 animals. 

To supply these parties with rations and forage, the remainder of the transportation was kept 
busy hauling from Yuma to the respective camps until the distance became too great for economical 
service from this point. 

When the party working toward the coast had crossed the desert and entered the region of 
the Coast Eauge of mountains its base of supplies was changed to San Diego, and to supply the 
the party working eastward, after getting beyond convenient wagon communication with Yuma, 
stores were shipped by rail to points on the Southern I'aciflc Eailway and hauled, thence to the line 
by wagons. 

At Yuma the commission office, including the draftsman and photographer, was retained until 
late in May, when that camp was abandoned. 

The senior commissioner then took charge of the monument party just organized for work on 
parallel 31° 20', i)roceeding to i!fogales for this purpose. The second commissioner went to Buenos 
Ayres, near the boundary, south of Tucson, to take charge of the survey party approaching that 
point from the west, and the third commissioner went to San 1 )iego to supervise the party working 
in that direction tlirough the Coast Range of mountains. 

The monument party was made up from the men and transportation which had been engaged 
in hauling between Yuma and the survey camps, with some necessary additions and modifications. 
Its organization was as follows: One commissioner, Lieut. Col. J. W. Barlow; B. A. Wood, 
assistant engineer; T. H. Logan, quartermaster and overseer; D. E. Payne, photographer and 
painter; 2 rodmen, 1 blacksmith, 1 stone mason, it teamsters, 5 laborers, 1 cook, and 2 helpers; a 
total of 21 persons. 

The transportation consisted of 3 baggage wagons, 1 truck wagon, 2 water-tank wagons, 2 
spring wagons, 5 horses, and 24 mules. 

This party as above organized assembled at 2fogales in May, 1893, and took up the work of 
locating and erecting monuments on parallel 31° 20', eastward from the one hundred and eleventh 
meridian. 

These three organizations were continued, with some changes, until the completion of their 
duties. During this season the aggregate force employed reached the maxinuim, being 80 men 
and 22 wagons of all classes. 

The party working westward completed the survey to the Pacitic September 23, lS9.i, and, 
with the exception of those retained for special office work, the members were discharged and the 
transportation sold. 

The other party was engaged on its work in the field until the 20th of October, when, having 
reached the one hundred and eleventh meridian, it was transferred to Tucson, where the disbursing 
office had been previously established, and there disbanded. The majority of the men were 
discharged, and such transportation as was no longer required for the monument party was sold. 
The assistant engineers and instrument men were transferred to the office in San Diego for 
temporary service reducing notes and preparing field maps of their work. 

After the survey parties were disbanded, the only field force retained was the monument 
party, which, having finished its work on parallel 31° 20' and the meridian section, in aSfovember, 
1893, took up the work of locating and erecting monuments westward from the one hundred and 
eleventh meridian. 

On taking the field again, after its reorganization at Tucson, this party was considerably 
strengthened to meet the increased difficulties on this part of the boundary, and consisted of the 
following men and transportation: One commissioner, Lieut. Col. J. W. Barlow; B. A.Wood, 
assistant engineer, in special charge of location; D. It. Payne, photographer and overseer; J. T. 



UNITED STATES AND MEXICAN BOUNDARY. 13 

Amos, quartermaster ami clerk; M. E. Cnnniugham, wagon master; Jolm Duncan, foreman of 
laborers* Joe H. Wheeler, I'odman; 1 blacksmith, 1 stone mason, 9 laborers, 9 teamsters, 2 cooks, 
and 2 helpers— a total of 31 men; 2 spring wagons, 1 buckboard, 3 water-tank wagons, 5 baggage 
wagons, 1 truck wagon, 5 horses, and 36 mules. 

The commissioner met with a severe accident early in December which compelled him to leave 
the field for several months. General charge of operations was then given to B. A. Wood, assistant 
engineer, whose zeal, energy, and intelligence are worthy of special mention in connection with 
this part of his service. 

The above organization of the monument party was continued while operating between the 
one hundred and eleventh meridian and the Colorado Eiver. On reaching Yuma the question 
of sui)ply became much simplified, and the force was considerably reduced. The supply camp, 
hitherto a necessity, was discontinued, and the surplus transportation sent overland under charge 
of Mr. Amos, to San Diego, where it was subsequently sold. Mr. Wood's services being required 
in the office at San Diego, ]Mr. Ingram relieved him at this point. 

The following organization was that employed in monument location and erection from the 
('olorado Eiver to the Pacific: E. L. Ingram, assistant engineer, in charge; D. R. Payne, overseer 
and photographer; M. E. Cunningham, wagon master; 1 blacksmith, 1 cook, 1 helper, 2 packers, 
3 teamsters, 5 laborers; a total of 10 persons. 

The transportation consisted of 1 spring wagon, 1 buckboard, 2 baggage wagons, 2 water- 
tank wagons, 1 truck wagon, 3 horses, and 26 mules. 

Theie were employed in the office at San Diego at this time upon clerical and preliminary 
map work : L. Seward Terry, secretary and disbursing clerk ; J. L. Van Ornum, assistant engineer; 
J. F. Hayford, assistant engineer; B. A. Wood, assistant engineer; James Page, computer; P. D. 
Cunningham, computer; P. A. Mosman, computer; Joseph Thompson, assistant clerk. 

This otlice force was reduced as rapidly as the services of these assistants could be spared. 

The monument party completed the erection of monuments to the Pacific in June, 1894, when 
the party was disbanded and the transportation and cami) equipage sold. The assistant engineer 
and the photographer joined the office force in San Diego, and were engaged in preparing the 
records of their work until the fall, when the entire commission adjourned to ineet again iu 
Washington in October, 1895, to complete the reports and maps of the expedition. 

It has been previously stated that the principal assistants, who were engaged at the begin- 
ning of operations, continued with the expedition until the close of the work for which they were 
employed. It is proper to add in the case of each of these gentlemen, viz, Messrs. Van Ornum, 
Hayford, Ingram, and Wood, that they all brought to bear upon their duties rare intelligence 
and excellent previous training, and throughout the difficult and arduous work devolving upon 
them were ever willing and prompt to further the interests of the commission. To them is due 
large ci-edit for the successful completion of the survey and the erection of the monuments. 

The same might be said of Mr. L. S. Smith, who, holding the position of transitman from the 
beginning, was advanced in pay and responsibility, and is especially deserving of commendation 
for efficiency in investigating the causes of stadia error. 

The services of Mr. A. F. Woolley, jr., transitman, were also valuable and appreciated during 
the several months that he remained with the expedition. 

It is also ijroper to mention, in this connection, the services of Mr. James Page, computer 
and transitman, for thorough efficiency, and those of Mr. P. D. Cunningham, a most zealous and 
conscientious young engineer, who rose from the position of levelman to that of assistant engineer. 

Messrs. C. W. Speiermann, Ernst Franke, and H. B. Finley were faithful, industrious, and 
tlioroughly conscientious assistants, who rose from subordinate positions to places of higher 
responsibility and pay during the progress of their work. 

Maj. T. H. Logan deserves especial mention for rare skill, zeal, and industry in managing men 
and transportation in the field, and would have undoubtedly continued to the end except for 
physical disability. 

Mr. L. Seward Terry, secretary and disbursing clerk, performed his delicate and responsible 
duties from the beginning to the close of operations with entire satisfaction, combining in his 
methods clerical ability of high order with rapidity of execution and extreme accuracy of detail. 



14 



UNITED STATES AND MEXICAN BOUNDARY. 



Mr. J. T. Amos, assistaut clerk and assistaut quartermaster, was a man of ability and 
sterling- integrity, conscientiously performing the duties assigned to him. 

Among the more subordinate members of the expedition were several whose good conduct and 
pluck under adverse conditions were conspicuous, serving in great measure to prevent accidents 
and delays in the field. In this list should be mentioned M. E. Cunningham, hired as teamster, 
and afterwards promoted to wagon master; John Duncan, also a teamster, and promoted to 
master laborer upon monument work. 

Among the most deserving rodmen were Joe H. Wheeler, Thomas Evans, Albert Lang, W. T. 
Simpson, Albert Davis, and Eugene Gill. 

Of the teamsters and packers whose services M'ere specially praiseworthy were W. P. Blair, 
W. F. Mallory, Jack Nimo, Andrew Linder, John Groves, Charles Kohrer, and Eobert Lynch. 



Officers of c 



rt wilh Intel-national Boundary 



Datf cif joinin^r.' I>ate of relii 



A. C. Ducat, jr.... 

P.E. Trippe 

-T. K. Sejburn 

E. A.Mearns 

:;. G.Paxton 

T.G.IrvinJr 

F.N.Kingsburi-.. 
W. P. Jackson .... 

W.C.Eawolle Capta 

R. B. Bryan First lientenaiit | do 

J. R. Seyburn Second lieutenant Twenty-fourth Infantry. 



First lieutenant Twenty-lnurlb Infantry 

do Tenth Cavalry 

Second lientenant Twenty-fourth Infantry 

Captain Medical Depart 

Second lieutenant ! Tenth Cavalry 

First lieutenant Second Cavalry , Apr. 

Captain , do I July 

Second lieutenant Twenty-fourth Infantry 1 Aug, 



23, 1892 


Feb. 9, 1892 


29, 1892 


Feb. 20,1892 


9, 1892 


Aug. 10, 1892 




id Cavalry 



M.C.Wossells ' Captain do 

H. E. McYay First lieutenant i Medical Departine 

F. A. Winter do 

G. R. McMaster , Second lieutenant ] Twcntyfourth Infantry 

E. A. Mearns Captain ■ Medical Department 

S. V. Ham Second lieutenant , Twenty-fourth Infantry 

B. W. Leavell First lientenant do 

W. H. Bean do , Second Cavalry Dec. 



.Do. 



Sept. 


1,1892 


Apr. 


-,1893 


Sept. 


14, 1892 


Kov. 


9,1892 


Nov. 


-,1892 


Dec. 


6.1892 


.do 


Apr. 


17,1893 


Apr. 


17, 1893 


Nov. 


-, 1893 


June 


— , 1893 


Oct. 


— , 1893 


July 


22, 1893 


Sept. 


8, 1894 


Oct. 


10, 1893 


Nov. 


5, 1893 


Oct. 


19, 1893 


Dec. 


20, 1893 


Dec. 


20, 1893 


Aug. 


4, 1894 


Aug. 


19, 1894 


Oct. 


2,1894 



Xumher of en listed men > 



International Bonndary Commisaii 



' January 

February 
I Maicb 
I Vpiil 
• Ma\ 

I July 



Septi 1 
( )( toher 
NoAen.bii 
Dei emlx i 



Date. 
1892 



October 

Deceinbei 

Januar\ 

M in h 
Api 





1893. 




M.} 


29 


1 lanuar\ 




J-> 


June 


29 


Uhiuir\ 




15 


July 


23 


i Mircli 




4> 


August 


13 


Apnl 




41 


Sept. ml). 1 


15 


Ma\ 




43 


1 





UNITED STATES AND MEXICAN BOUNDARY. 15 

CHAPTER II. 

GENERAL DESCRIPTION OF THE COUNTRY ADJACENT TO THE INTERNATIONAL BOUNDARY LINE. 

Any general description of the country adjacent to the international boundary line between 
the Rio Grande and the Pacific must of necessity give au incomplete idea of its appearance to one 
unfamiliar with the arid regions and the peculiar character of its fauna and tloia, for probably in 
no section of the Fnited States of equal extent is the rainfall so small and the summer heat so 
intense. The average annual precipitation along the entire boundary is but about 8 inches, and 
on the Yuma and Colorado deserts but 2 or 3 inches, a deficiency which will be made more significant 
to the ordinary reader when it is stated that the boundary line, although having a total length of 
about 700 miles, crosses but five permanent running streams between the Rio Grande and the 
Pacific and this, too, although crossing most valleys and mountain ranges nearly at right angles, 
the direction most favorable for encountering all existing streams. 

From the summer of 1890 to that of 1893 the entire country between tlie Rio Grande and the 
Colorado suffered from a drought of unprecedented duration and severity, the effects of which were 
intensified by the overstocked condition of the ranges. This state of affairs added greatly to the 
difficulties and expense of the survey. Vegetation was parched, water holes dried up, and scarcely 
any grass was left by the famishing cattle. This long drought was broken by abundant rains in 
July and August, 1893, but not until the stock-raising interests had suffered severely. 

The small rainfall of this region generally occurs at two periods of the year — midwinter and 
midsummer — the latter rainfall the greater and by far the nu)St important; consequently this period 
is known as the "rainy season." The summer rains generally commence about the 1st of July iind 
cease sometime between the 1st and 20th of September. It is soon after the first of these rains that 
vegetation in this region begins to assume a spring-like character. Leaves burst forth, the hills 
and valleys are covered with grass, and a bewildering profusion of wild flowers covers the entire 
country. As if conscious of the short duration of the rainy season, these grow with great rapidity, 
and their seeds mature ere the rains cease. In a month or so thereafter they have again assumed 
the somber colors typical of fall and winter. Thus in the short space of three or four mouths 
vegetation here enjoys its spring, its summer, and its autumn. 

Before going more into details it may be well to note certain general characteristics of this 
I'egion which at once strike the ordinary traveler. 

These are the bare, jagged mountains rising out of the plaius " like islands from the sea;" the 
abundance of the evidences of volcanic action in times geologically recent; the parallelism of the 
mountain ranges with one another, aiul with the Pacific Coast; the general absence of trees; the 
preponderance of evergreen vegetation, and its dull, leaden-green hue; tlie prevalence of thorns 
in nearly all vegetation; the general absence of fragrance in flowers; the resinous character of 
the odor of the most common trees and shrubs, and the abundance and large size of the cactus. 

The entire country along the boundary is thinly settled, the principal settlements within 20 
miles of the boundary on either side being at Lake Palomas, Hachita, the Sulphur Spring Valley, 
La Morita, the San Pedro Valley, the Huachuca Mountains, the Santa Cruz Valley, Oro Blanco, 
Arivaca, the Baboquivari Valley, the Papago rancherias of Pozo Vei'de, Cobota, and Pozo de 
Luis, the Sonoyta Valley, the Colorado River Valley, and tlie country between the summit of the 
Coast Range and the Pacific. The only towns within the limits above mentioned are Bisbee, 
Santa Cruz, Xogales, Yuma, and San Diego. With the exception of these towns and settlements 
the rest of this zone of about 24,000 square miles contains less than loo permanent inhabitants. 

Milling and stock raising comprise the principal occupations of the settlers, but at the time 
of the survey both of these were in a very depressed condition, owing in the one case to the low 
price of silver, and in the other to tlie long drought of three years' duration and to the overstocked 
condition of the ranges. An exception to this depression, however, was found at Bisbee, Ariz., 
where are located the mines and reducing works of the Copper Queen Company, wliich are reported 
as returning excellent profits to the owners. 

Although the soil in many places is very fertile, yet the great scarcity of water renders it 
impossible for the inhabitants to carry on agriculture, except to a very limited extent. 



16 UNITED STATES AND MEXICAN BOUNDARY. 

But for sandy stretches on tbe deserts many miles in length, and rough passes through the 
mountains, the natural roads along the boundary are very good. With the exception of the 
Colorado River section, there exists, however, no practicable wagon road along any one of the six 
sections of the boundary line and witliiu a reasonable distance of it, which lies either entirely iu 
the United States or in Mexico, a fact which even now, in spite of the small number of inhabitants 
along the boundary is the cause of considerable unavoidable inconvenience to travelers when 
customs otlicials are encountered. 

It is rather remarkable that an arbitrarily chosen boundary line like the one under discussion, 
should, between the Rio Grande and the Colorado River, follow almost exactly the summit of the 
divide which separates the waters flowing north into the United States from those flowing south 
into Mexico. 

Having given the foregoing general description of the boundary line, the different sections, 
beginning at the Rio Grande, will be briefly described in turn. 

^Section 1, jxtraUel 31° 47'. — The Rio Grande in the vicinity of El Paso, Tex., is a variable stream 
with turbid waters carrying an immense amount of sediment, and as a consequence it is bordered 
by alluvial bottoms, through which by erosion, it is continually changing its bed. Floods generally 
occur in June and July, but during the greater part of the year the volume of flow is comparatively 
small and the river can readily be forded. In dry seasons it ceases entirely to flow for weeks 
at a time. In the immediate vicinity of the Initial Point of the boundary the mountains on 
either side encroach on the river, and as a consequence its banks there are more stable and its 
changes of bed smaller in extent. 

Leaving the Rio Graude the boundary line crosses the Muleros Mountains, a rugged, broken 
mass, almost destitute of vegetation, composed of a curious and bewildering intermixture of 
stratified limestone and igneous rocks. Between H and 3 miles west of the summit of the Muleros 
Mountains the line reaches, by a rather abrupt ascent, the surface of a wide, sandy mesa, about 
4,000 feet above sea level, over which it continues for a distance of about 48 miles. Mile after 
mile this mesa stretches in an endless monotony of fiat, rolling ridges and shallow valleys, with not 
a tree to relieve the dreary aspect of the landscape. The earth is covered with a coarse, brownish- 
yellow sand, which supports, in places, an excellent growth of black grama grass, and a stunted 
growth of greasewood, mesquito, yucca, and " ochetilla" (Fouquieria splendens). 

On the edge of this mesa lies the Sierra del Potrillo, a cluster of bare, rounded mountains, 
giving evidence, by extinct craters and the extent of the " mal i)ais" in its vicinity, of considerable 
volcanic activity in the past. Toward its western edge the mesa becomes more rolling, and rocky 
hills covered with broken lava are scattered at intervals over its surface. 

Descending from the mesa by a well-marked and rather abrupt descent, the line passes for a 
distance of about 17 miles over a broad, level valley, bare of vegetation, and having a soil composed 
of a stiff clay sediment, which becomes almost impassable when wet. This valley lies between tbe 
Floridas and the Tres Ilermanas mountains, and extends in a north and south direction. 

Down this valley, and connecting at Deming, N. Mex., with the Southern Pacific Railway, 
a railroad luid been located a year or two previously, and the grading extended from Deming to a 
)>oiiit several miles below the boundary, when work was suspended on account of financial 
ditticulties. Anticipating the completion of this railroad a town site was laid out where it crossed 
the boundary line; lots were sold, and a small settlement, bearing the name of Columbus, was 
started. 

A mile or two south of this settlement commences a chain of shallow, marshy lakes, whose 
waters are strongly impregnated with alkali, and which are connected with one another by a small 
running stream. This chain, called Lake Palomas, terminates in a broad, shallow lake, several 
square miles in area, with no visible outlet. When the water in this lake is low its shores are 
covered with an alkaline deposit, 2 or 3 inches in depth, resembling snow. 

About 5 miles south of the boundary, on the western edge of the chain of lakes, and near some 
line, bold springs, was located the Mexican custom-house, which had been recently moved there 
from Asceuciou as a ])unishment for an outbreak against the Government at that place. 
One troop of cavalry was quartered there at the time, giving to the place an unexi)ected appear- 
ance of life and activity. The peculiar chain of lakes constituting Lake Palomas is supposed to 
l)e <lne to the reappearance of the waters of the Mimbres River after their long underground 



UNITED STATES AND MEXICAN BOUNDARY. 17 

journey. Beyond these lakes they reappear no more. Lake Palomas is the first natural water 
encountered near the boundary after leaving the Eio Grande, distant 75 miles by road. Water 
had been obtained, however, before reaching Columbus, from a well at a ranch on the edge of the 
valley about 3 miles northwest of Monument 15. 

An excellent road leads from Deming, via Columbus, to the Mormon settlements in Chihuahua, 
but the road to El Paso, after leaving the Mimbres Valley, is sandy, very heavy, entirely withoiit 
water, and practically impassable unless an abundant supply of water is carried along. 

After leaving the valley of the Mimbres the line passes for several miles over the rolling, 
grass-covered ridges lying south of the Tres Hermanas Mountains, a region marked by abundant 
evidences of past volcanic activity. 

Beyond these ridges a wide, flat valley is crossed, and the line then passes over the Carri- 
zalillo Mountains, a spur of the Sierra Boca Grande to the southwest. On these mountains were 
seen the first trees encountered since leaving the Eio Grande; a few stunted cedars, which found a 
precarious growth amid the broken basalt which everywhere covers the surface of the mountains. 

A little over i miles north of Monument 33 lies Carrizalillo Spring, the first water after leav- 
ing Lake Palomas. This spring furnishes an abundant supply of good water, most of which is 
utilized in supplying the needs of a cattle ranch located in the immediate vicinity. 

Beyond the Carrizalillo Mountains the line crosses a broad, grass-covered valley, 10 or 12 
miles wide; then it enters the Apache Mountains, where it terminates at Monument 40, a fine, 
cut-stone monument, with suitable inscriptions. These mountains contain an abundance of low- 
grade silver ore, from whi(>h but little profit is derived, owing to the scarcity of water and the 
cost of transportation. A good road leads from this vicinity, via Carrizalillo Spring, to Deming, 
X. Mex., and another, via Hachita, to Separ, a station on the Southern Pacific Railway. 

Sevtion 3, the meridian section. — Commencing nt Monument 40 the lines passes, for a distance 
of about 5 miles, over the Apache Mouutaitis and then over a broad, fertile valley, covered with a 
thick growth of mesquite, greasewood, etc., on its northern and western border, and with excellent 
grass in other places. This valley is bounded on the northwest by the majestic Sierra de la 
Hacheta (locally known as the Big Hatchet Jlountain), and stretches away to the south and east 
to unite with the valley of the Corralitos Eiver. 

A little over a mile east of Monument 4(1 are situated the " Ojos de los Mosquitos," yielding 
a plentiful supply of water, impregnated with alkali. From this point good roads lead to Carri- 
zalillo Si>ring, Dog Spring, Ascencion, and the settlements along the Corralitos River. From 
Monument 4(5 the portion of the valley over which the line passes rises with a gentle slope toward 
the south, until the foothills of the Dog Mountains are reached, when the section terminates at 
an elevation of about 4,900 feet above sea level. This point is marked by Monument 53, a fine, 
cut-stone monument, identical in appearance with that marking the beginning of the section. 

Section S, parallel 31° 20'. — From Monument 53 the line passes for several miles over the rough 
hills south of the Dog Mountains, thence across the east branch of the Playas Valley, the White- 
water Hills, the west branch of the Playas Valley, and the San Luis Mountains, all in a distance of 
about 35 miles. A little over a mile north of Monument 55 is Dog Spring (Ojo del Perro), at which 
is located a cattle ranch, and which furnishes a supply of excellent water suflicient for several 
thousand head of animals. The country along this part of the boundary is covered with excellent 
grass, which attbrds xJasturage for numerous cattle and horses. 

A little over (5 miles north of Monument 58 is Alamo Hueco Spring, where the supply of water 
is both excellent and abundant. At the south end of the Whitewater Hills water can generally 
be found, but in very dry seasons the quality is poor and the supply very limited. In such cases, 
however, a plentiful supply can be obtained about 6 miles southwest of this point, at " San Francisco 
Water." This entire region abounds in game, and is a veritable hunter's paradise. Hundreds of 
antelope roam over the valleys, and deer, bear, and turkeys are plentiful in the mountains. 

On the summit of the San Luis range, which here forms the ''continental divide," the boundary 
line attains its greatest elevation, about 6,000 feet above the sea. About 4i miles north of the 
boundary the road from Dog Spring crosses the mountains by an excellent pass known as San 
Luis Pass. Two miles north of the line is another pass less traveled than the former, but shortening 
the distance considerably. 



18 UNITED STATES AND MEXICAN BOUNDARY. 

To the iioi'th of San Luis i'ass the range gradually rises in height to Animas Peak, which prac- 
tically marks its northern extremity. To the south of the pas.s the mountains become higher anil 
more rugged, and the range stretches south into Mexico as far as the eye can see, forming here the 
axis of the Sierra Madre, and presenting a wild and picturescjue beauty singularly fascinating. 
On the foothills and lower slopes the prevailing rock is red basalt, while on the summit and upper 
slopes it is apparently an igneous rock of volcanic origin resembling granite. The valleys at the 
base and lower slopes are dotted with evergreen oaks, the acorns affording food for thousands of 
wild pigeons, while on the upper slopes are dense forests of junii^er, pine, fir, and Arizona cypress. 

A few hundred yards northeast of Monument 66 is situated San Luis Spring, which affords a 
moderate supply of fair water, and from which good roads lead to Lordsbiirg and Separ, on the 
Southern Pacific Railway. No settlements are now found in this vicinity, those at one time 
existing having been abandoned during the raid of the noted Apache chief, Geronimo. Pros- 
pective settlers are now deterred through fear of a small band of renegade Chir-ica-hua Apaches, 
who, under the leadership of the redoubtable " Kid," still continue their murderous raids in the 
vicinity, and as yet have succeeded in escaping the pursuit of the numerous detachments of troops 
.sent against them. 

Leaving the San Luis Mountains the line passes over the Animas Valley and the Guadalujie 
Mountains and descends into the San Bernardino Valley. The Guadalupe Mountains where 
crossed by the Ijoundary line are in reality but the broken. Jagged edge of a terrace, marking a 
descent of about 1,400 feet from the Animas Valley to the San Bernardino Valley. For the most 
part bare of trees, they present to the eye a confused mass of peaks, crags, ridges, and cafions. 
Through these the old emigrant road makes its way by sudden turns and steep descents until it 
enters the Guadalupe Cafion, which gradually widens, improving tiie character of the road 
thereby. This rough and difficult passage, called Guadalupe Pass, is the only route through the 
mountains within many miles north or south of the boundary. 

IVlonument 71 in these mountains marks the intersection of the boundary line between Arizona 
and New Mexico with the international boundary line. 

By local repute the boundary line between Souora and Chihuahua is said to intersect the 
international boundary line at the same spot; but as this boundary line is generally shown as 
the axis of the Sierra Madre, it would seem that the intersection should occur at Monument 65, 
on the San Luis Mountains. Water was found at a small spring in Guadalupe Canon, and also 
in wells near the point where the boundary line crosses the canon. 

In San Bernardino Valley the line crossed the first running water since leaving the Eio Grande, 
over 102 miles distant. In this valley, a few miles north of the boundary line, rises San Bernardino 
Creek, the most northerly tributary of the Yaqui River. Numerous springs are found in the 
valley, and thousands of cattle seek pasture on its marshy surface. A large ranch is established 
at some fine springs just north of the line, while a short distance south of the line are found the 
ruins of a bastioned adobe fort and numerous outbuildings, marking the site of a floui-ishing 
presidio established during the Spanish rule. Good roads lead from San Bernardino to Tombstone 
and Bisbee. 

Crossing the gravelly mesa west of the San Bernardino Valley the line passes over the Per- 
rilla Mountains, which, with the Swisshelm Mountains to the north, form a spar of the Chir-i-ca-hua 
Mountains, and divide the San Bernardino Valley from the Sulphur Spring Valley. A short 
distance south of the line is a very j)rominent, flat-crested peak, Cerro Gallardo, locally known 
also as " Niggerhead," which forms a prominent landmark. About 2 miles southeast of Monument 
SI was located a " vinateria," where a supply of good water was obtained from a shallow well. 

From the Perrilla Mountains the land slopes gradually and uniformly down to the middle 
of the valley, and by a similarly long and tedious slope the foothills of the Mule Mountains are 
reached. Several settlements are located in this valley, as water can always be obtained by 
sinking wells to a moderate depth. 

Crossing this valley the boundary line passes through a gap near the southeastern extremity 
of the Mule Mountains, thence along the north slope of the valley lying between the Mule 
Mountains and the Sierra San Jose until the valley of the San Pedro River is reached. 

About 10 miles north of the boundary line, in the Mule Mountains, is located the prosperous 
mining town of Bisbee, a place of about 2,000 inhabitants. About 20 miles to the northwest of 



UNITED STATES AND MEXICAN BOUNDARY. 19 

Bisbee is Tombstone, once one of the great mining camps of the world, but now containing about 
1,500 inhabitants, and bearing on all sides evidences of depression and decay. 

About 4 miles south of Monument 90 is located the Mexican customhouse of La Morita, 
recently moved there from the San Pedro River. From the Mule Mountains to the end of 
parallel 31° 20' the country is fairly thickly settled, and the distance between watering places 
nowhere exceeds 10 or 12 miles; consequently in this region it is not necessary, as heretofore, to 
describe all available water in detail. 

The San Pedro lliver, in the vicinity of the boundary line, is ordinarily a stream of about 15 
feet in width and 6 or 8 inches in depth, fringed with a fine growth of cottonwood and willow, 
and possessing the distinction of being the only southern tributary of the Gila wliich has an 
uninterrupted flow throughout its entire length. The valley bordering the river is very fertile, 
but the bed of the river has sunk so deep that irrigation is attended with many obstacles, and 
consequently but a very limited portion of the valley is under cultivation. On the east bank of 
the San Pedro, a few miles south of the line, is the little village of San Pedro, where until very 
recently was located the Mexican customhouse, now removed to La Morita. A good road leads 
from Benson, through the Sau Pedro Valley, to the higli table-lands of northern Souora. 

From the San Pedro River the slope rises rapidly, but uniformly, to the Huacliuca Mountains, 
over the southeastern end of which the line passes at an elevation of about 6,100 feet. These 
mountains and their lower slopes are covered with a heavy timber growth generally similar to 
that found on the San Luis ]\Iountains. They are the highest embraced within the limits of the 
survey, attaining, at a point about 4 miles noi'th of the boundary, an elevation of about 9,400 feet. 
At the foot of the mountains, about 15 miles north of the line, is beautifully situated Fort 
Huachuca, an important post garrisoned by four companies of infantry and two of cavalry. 

From the Huachuca Mountains to the San Rafael Valley the line passes over a beautifully 
picturesque grazing country, badly cut up by canons, from which it descends into the San Rafael 
Valley, the name by which is known that portion of the valley of the Santa Cruz River lying east 
of the Patagonia Mountains and adjacent to the boundary line. 

The Santa Cruz River rises in the hills a few miles north of the boundary, flows south into 
Mexico for about 15 miles, then turns around the south end of the Patagonia Mountains and flows 
north, again crossing the boundary line, and continuing its generally northern direction, flowing 
for a short distance and then sinking beneath the sands, to reappear again, until it disappears 
finally a short distance beyond Tucson. The stream is bordered by a noble growth of cottonwoods, 
whose bright green leaves were a welcome sight after the ashen-green color of the vegetation 
previously encountered. That portion of the valley of the river which lies in JNIexico is very 
fertile, and a considerable part of it is under cultivation. The little town of Santa Cruz is 
picturesquely situated in this valley at the foot of the mountains, about 7i miles south of the line. 

In the San Rafael Valley, at La Noria, is situated the United States custom house, from 
which a rough road leads to Crittenden, on the Arizona and New Mexico Railway, and a good 
road down the Santa Cruz Valley and around the Patagonia Mountains to Is'ogales. 

Leaving the San Rafael Valley the line passes over the rough, oak-clad foothills of the 
Patagonia Mountains, which it crosses in a gap a short distance north of San Antonio Pass, at an 
elevation of about 5,(i00 feet. These mountains are quite pictures(iue, being heavily wooded, the 
growth consisting principally of oak, with a few conifers on the higher slopes. They are rich in 
minerals and contain some of the first mines worked by Americans in Arizona. The San Antonio 
Pass, an excellent one for pack animals, crosses this range a little south of the line and cuts off 
the tedious detour along the Santa Cruz Valley, 

From the Patagonia Mountains the line descends over a badly cut up hill country to the Santa 
Cruz River, which it crosses for the second time. The elevation of the river is about 3,675 feet, 
and it is somewhat singular that the two lowest points on the boundary between the west end of 
parallel 31° 20' and the Initial Point on the Rio Grande differ in elevation less than 16 feet from 
each other, and less than 23 feet from the Initial Point on the Rio Grande. The two points in 
question are at San Bernardino Creek and the second crossing of the Santa Cruz River, the former 
being the lower of the two. 

From the Santa Cruz the line begins to ascend, passing over a hilly country, the broken and 
cut up character of which increases to the termination of the line in the Sierra de los Pa,jaritos at 
an elevation of about 4,800 feet. 



20 UNITED STATES AND MEXICAN BOUNDARY. 

Nestling amidst tlie bills, in a narrow valley abont 8 miles east of the termination of parallel 
31° 20', lies the town of Nogales, containing about 3,500 inhabitants, and built on both sides of 
the boundary line, which passes tangent to the south front of the buildings on the United States 
side of International street. This street has a width of about 50 feet and lies entirely within 
Mexican territory. The grasping and overreaching action of the United States settlers in building 
right up to the boundary line results in many inconveniences to the customs officials and peace 
officers of the United States, who, in order to patrol this important street, must rely for permission 
to do so upon the kindness and courtesy of the Mexican officials. Open, yet lawful, evasions of 
customs duties result from the position of this street with reference to the boundary line, as in 
one somewhat noted case observed where liquors of United States manufacture were sold to the 
consumer in a saloon on the United States side of the line, while cigars of Mexican manufacture 
were sold by the same establishment from a stand in front of the saloon but on the Mexican side 
of the line, thus enabling consumers from either side to obtain, duty free, liquors and cigars from 
the same establishment. 

At Nogales are located both the United States and Mexican custom-houses, the latter a flne^ 
■well-arranged building, the annual customs receipts of which are very large, as Nogalesis situated 
on the railway which runs from Benson, Ariz., to Guaymas, on the Gulf of California, and is the 
only railway entering Mexico between the Rio Grande and the Pacific. 

Good roads lead from Nogales north t(5 Tucson, and south to Magdalena, Herniosillo, and 
Guaymas. 

Section 4, the azimuth line from the west end of parallel 31° 20' to the Colorado River. — A fine 
masonry monument. No. 127, situated in the Sierra de los Pajaritos, on the north slope of a steep 
ridge, marks the beginning of this section of the boundary line, which for about 21 miles continues 
in these mountains. 

The term " Sierra," as applied to them, is a decided misnomer, for unlike the mountains pre- 
viously encountered, they consist of a confused mass of rocky crags, peaks, fiat-topped mountains 
with vertical sides, enormous trachyte dykes, steep, narrow ridges, and deep canons, all mingled 
in startling confusion. The most common rocks are porphyry, red basalt, syenite, and volcanic 
breccia. Gold and silver veins are found in numerous places, and placer gold is obtained in most 
of the caiions. 

The mountains are covered with a fine growth of evergreen oak, juniper, and raanzanita, while 
magnificent walnut, sycamore, and ash trees line the caiions. Excellent grass covers the hills; 
thousands of beautiful wild flowers spring up on all sides during the rainy season; game is 
abundant, and the climate unsurpassed. From the highest part of these mountains the view is 
beautiful beyond description, and stretches away for 75 or 100 miles in every direction. 

Throughout this entire region, probably one of the roughest and most cut up in North 
America, there are no roads and but a few blind trails. Little or no water is to be found during 
the dry season, except by digging, although there is evidently a considerable underground 
drainage, as the Altar lliver, Arivaca Creek, and Nogales Creek, all permanent streams, derive 
their waters from the drainage of. these mountains, which were notable, not only on account of their 
beauty, but also because they constituted the last timber-covered mountains encountered on the 
survey until the Coast Kange was reached, and because in them was seen for the first time the 
strange and ungainly "giant cactus" (cereus giganteus), called "suguaro" by the Mexicans. 

Leaving the Sierra de los Pajaritos the line crosses in succession the Baboquivari Valley, the 
Baboquivari Mountains, and the Moreno Flat. 

Although absolutely bare of trees and bushes, it is hard to picture a more beautiful valley 
than the Baboquivari, in the vicinity of Buenos Ayres, during the "rainy season." To the 
northwest towers the striking Baboquivari Peak, venerated by the Papagos as the abode of their 
God; in the foreground is a wide lake, while in every direction stretch gentle swells and hollows 
covered with magnificent grass and with a profusion of wild flowers. Thousands of cattle and 
horses find pasturage in this valley, and stock raising would be very profitable did this condition 
of things last; but the ranges here, as in all places along the border, are overstocked; the lake 
dries up in the spring, and water has to be pumped from bored wells several hundred feet deep. 
This valley marks the eastern limit of the region along the boundary reached by the summer 



UNITED STATES AND MEXICAN BOUNDARY. 21 

"sea breezes" from the Gulf of California, which here were constant and refreshing. In the hills 
at the south end of the valley and a short distance below the line, is situated the Mexican custom 
house of Sasabe, while at Buenos Ayres, about 6 miles north of the line, is located the United 
States custom-house. 

At the foot of the Babo(iuivari Mountains (here called the Pozo ^'erde Mountains), a little over 
a mile south of the line, is located the Papago Rancberia of Pozo Verde, named from a hue spring 
in the vicinity, which is the only natural water, except that in the Sonoyta Valley, until the 
Colorado Kiver — 200 miles distant — is reached. This rancberia consists of about 35 adobe huts, 
and contains a population of about 150 persons, who own several hundred head of cattle and 
horses. Au excellent road leads from Tucson, via Buenos Ayres, La Osa, and the south end of 
the Pozo Verde Mountains, to Pozo Verde, while another and shorter road on the west side of the 
Baboquivari Mountains leads from Tucson, via La Ventana, to the same [dace. 

The broad valley west of the Baboquivari Mountains is called the Moreno Flat, from a 
mouutaiu of the same name on its west slope. The soil of this valley is very fertile and supjiorts 
a fine growth of mesquite. In seasons of normal rainfall the grazing is excellent, but as little 
rain had fallen during the loug drought preceding the survey, scarcely a blade of grass could be 
seen, while the surface of the entire flat was cut up by innumerable cattle tracks, leaving the soil 
loose and powdery for a depth of 2 or .'5 inches. 

In this valley, on July 3, 1893, was encountered a sand storm of frightful violence. About 4 
o'clock in the afternoon a dense, dark-brown cloud was seeu rising in the south, which presented a 
singularly threatening appearance. The sun, which until then had been shining brightly, was 
soon overcast, and in a few minutes after the cloud was first noticed the storm burst in all its fury, 
filling the atmosphere to a height of several hundred feet with the loose soil of the valley. In 
ten or fifteen minutes after the storm burst it became as black as midnight, respiration was almost 
impossible, and it was only by breathing through a handkerchief held in front of the mouth that 
suftbcatiou was avoided. In about half an hour the wind began to subside and the darkness to 
diminish, and finally, in a little over two hours after the storm commenced, the setting sun shone 
faintly through the particles of dust which still filled the air. 

Many sand storms were encountered during the progress of the work, but none so appalling 
as this in its suddenness, violence, and darkness, and uone so remarkable for the brevity of its 
duration. 

A few miles northeast of the Moreno Mountain, in the center of the valley, has recently been 
located a large cattle ranch, called La Ventana, at which a good supply of slightly alkaline water 
is pumped from two artesian wells, between eight and nine hundred feet deep. This ranch is 
the last white settlement in the United States near the boundary until the Colorado Eiver Valley 
is reached. 

From the Moreno Flat the line passes over a low saddle in the mountain of the same name, 
thence over the mesquite-covered flat northeast of the Cobota Eange, passing but a few yards 
north of the low, rocky, vertical escarpment which marks the most northernly point of this range. 
The flat terminates at the Lesna Mountains, a jagged trap-like range, composed principally of 
porphyry, and forming a spur of the Cobota Mountains. 

This range is bordered on both sides for a width of several miles by a luxuriant growth of 
mesquite, palo verde, palo fierro, and cactus. At the point where the line crosses is a remarkable 
peak, called Cerro de la Lesna, having vertical sides and two horn-like prominences, over the 
north one of which the line passes. About 6 miles southeast of this peak is the Papago Eancheria 
of Cobota, plentifully supplied with water from a shallow well. About 2 miles west of Cobota is 
a Yaqui and Papago liancheria, called Pozo de Luis (and also El Vauori), situated at the west 
entrance of the pass through the Cobota Mountains. At these rancherias were seen large herds 
of cattle and horses, ail in excellent condition, and the former superior to any others seen on the 
survey. The water at Pozo de Luis is the last encountered until Sonoyta, distant 50 miles by 
wagon road, is reached. 

About 2 miles north of Cerro de la Lesna a few "renegade'' Papagos, called "Los Coches," 
were located at a well which is reputed to yield a very unreliable supply of water. These Indians 
were fugitives from Mexican justice, having been outlawed for their numerous crimes. They were 



22 UNITE]! STATES AND MEXICAN BOUNDARY. 

iinicli dreaded by tbe few travelers tbrough tbis regioii, but failed to sustaiu tbeir reputatiou, for 
ou approacb of tbe working parties tbey abandoned tbeir raucberia witb all its contents and did 
not return until tbe survey bad progressed many miles beyond. 

Tbe country along tbe boundary on botb sides of tbe line between tue Baboquivari Mountains 
and tbe Sierra de las Tinajas Altas forms a part of tbe Papagueria, a region probably as little 
traveled and as little known by wbite men as any in our country. 

Tbe Papagueria, as indicated by its name, is settled almost exclusively by tbe Papagos, a 
tribe wbicb numbers several tbousand persons, only about one-balf of wbom reside witbin tbe 
limits of tbe United States. Tbis entire region is a hopeless desert, on wbicb none T)ut these 
hardy Indians could tind subsistence. At tbe few permanent wells and springs are located tbeir 
rancberias, from wbicb, as soon as the July rains begin, they scatter over the Papagueria to their 
numerous " temporales." 

These "temporales" are located near some natural or artificial water hole, from which their 
supply of drinking water is obtained, and are in close proximity to cultivable lands. Tbe 
bouses are generally built of adobe, and tbe fields protected by rude fences of mesquite brush. 
In tbe "temporales," so deserted and forlorn during most of the year, a wonderful change takes 
place witbin a day or two after the first rain of summer. Where before all was desertion and 
silence all is now life and activity. Cattle and horses are being driven to pasture; bouses and 
fences repaired; Indian corn, beans, pumpkins, and melons planted, dams repaired, and shallow 
irrigation ditches cleaned out. 

Ill many cases the natural rainfall alone is relied upon and no recourse is had to artificial water 
boles or ditches. Owing to the fertility of tbe fields and tbe beat of tbe climate the crops mature 
rapidly, and in three or four months the " temporales" are again silent and deserted. Occasionally, 
when the winter rainfall is unusually great, crops of wheat are also grown at the "temporales." 
During June and July the food supply is greatly augmented by the fruit of the giant cactus, which 
ripens then, and which is gathered in great quantities by tbe squaws. Some of it is eaten fresh; 
some dried for winter use; some boiled into preserves; from some a beautiful carmine sirup is 
made, and not a little is consumed iu tbe manufacture of a slightly intoxicating fermented drink. 
Another drink, nonintoxicating and very refreshing, is made from a minute, gum-coated seed 
called "chilla," which partly dissolves when placed in water. 

Every year the Papagos make long excursions to the mountains to gather acorns for food, and 
in times of scarcity tbey make great use of mesquite beans and seeds of certain grasses. They 
are an intelligent tribe, peaceably disposed both toward the United States and Mexico, but 
possessing an undying hatred for their old enemies, tbe Apaches. The men are well armed and 
are skillful hunters, and the young squaws far above tbe average in good looks. Like the Yumas, 
Oo-co-pabs and Diegenos, the Papagos proved tborouglily honest as far as tbis expedition was 
concerned, not a single piece of property and not an article of food having been stolen, and this, 
too, notwithstanding tbe fact that throughout the Papagm'-ria, owing to the great scarcity of 
water, the escort was always camped many miles from the working parties. 

Tbe Papagos look witb longing for the coming of "Moctezuma," their promised Messiah, who 
is to right alJ wrongs and to make the arid desert a garden and his people greater than all others. 
Except in tbe vicinity of civilization, their bouses are built with tbe doois facing the east, so that 
when Moctezuma comes with the rising sun be may find all doors open for him. 

Leaving Cerro de La Lesua the line crosses a broad, mesquite covered flat, about IS miles in 
width, and then passes in succession over tbe east branch of tbe Sierra de la Nariz, the Santa 
Kosa Valley, in which is located a " temporal " of tbe same name, and the west branch of the Sierra 
de la Nariz. Tins range is a spur of the Sierra del Ajo on the north, and is a bare, rugged mass 
of igneous rocks overlaid with a capping of broken black lava, which gives it a most dreary and 
somber aspect. On the east branch of the range just north of the line is a most interesting and 
elaborate system of fortifications, formed of walls of lava about waist high and 2 or 3 feet in 
thickness, excellently located for defending the crest against assault. These fortifications were 
said to have been constructed by tbe Papagos for defense against Mexican troops when tbe region 
belonged to Mexico; but this is a mere tradition, which could not be verified. 

At the south end of tbe east branch of tbe Sierra de la Nariz is located the Nariz Temi)oral, 
a little south of tbe road from Altar to Sonoyta. 



UNITED STATES ANU MEXICAN BOL-NDAKY. 23 

After leaving the Sierra de la Nariz the line passes over a valley about 12 ujiles wide and then 
crosses the Sierra de Sonoyta, at the end of which flows the Sonoyta Elver, a stream about 12 feet 
wide and 6 or 8 inches deep. 

Sonoyta was formerly quite a flourishing little agricultaral village, but heavy rains caused 
the river bed to sink so deep below the level of the surrounding lands that irrigation was attended 
with many difliculties, and by a lamentable want of energy and united action in constructing a dam 
to raise the level of the water the village fell into decay, family after family moving away, until 
now scarce a half dozen Mexican families remain, while abandoned fields and magnificent fig trees, 
dying for want of water, are painful reminders of past prosperity. About 8 miles west of Sonoyta 
is situated the Mexican custom-house at Santo Domingo, on the ranch of Don Cipriauo Ortega, who 
cultivates about 300 acres of land, the largest area under cultivation by one person near the entire 
boundary. About 6 miles west of Sonoyta is the little settlement of Quitobaquita, near some fine 
springs, which burst out of the hills on the United States side of the line, but serve to irrigate a 
field near the river, on the Mexican .side. Two families of Mexicans reside here, but the houses 
near the springs all lie within the limits of the United States. The valley of the Sonoyta is quite 
fertile and must at one time or another, as shown from evidences now remaining, have been almost 
all under cultivation. The Sonoyta Eiver drains a very large basin, embracing almost the entire 
country between the Cobota Mountains and its actual source, a mile or so east of Sonoyta. For 
a short distance it continues as a running stream, then disappears, reappearing in the vicinity 
of Santo Domingo. Beyond this point it reappears, as a succession of shallow pools only, in two 
places, Agua Dulce and Agua Salada, the character of the water at each place being indicated by 
its name. Agua Salada is about 11 miles south of west of Quitoba((uita. With the exception of 
the Mexican families located at the settlement before mentioned the other inhabitants of the 
Sonoyta Valley consist of Papago Indians, who engage in agriculture and placer mining, liich 
gold mines have been located in the vicinity of San Antonio, about 30 miles south of the line, but 
the absence of water renders it extremely difiicult and expensive to develop them. About the 
same distance southwest of Quitobaquita is the prominent Sierra Pinacate, near the foot of which 
are immense salt beds, at present almost inaccessible on account of the sandy roads and the 
absence of water. 

From (Juitobaquita good roads lead to Altar, Mexico (via the Xariz Temporal), Gila Bend, on 
the Southern Pacific Railway (via the old Ajo Mine), and Tucson, Ariz, (via Nariz Temporal, Pozo 
de Luis, and Cobota, uniting with the road from La Ventana to Tucson a few miles north of the 
former place). On all of these roads, however, there are stretches of from 40 to 50 miles without 
water, and a. journey on them should never be attempted in summer unless an ample supply of 
water is carried along. 

Probably nowhere ahing the boundary cioes the cactus growth attain such luxuriance as in the 
foothills of the Sonoyta Valley. The giant cactus here attains a height of 40 or 50 feet and forms 
perfect forests, if the word forest can iiroperly be applied to a collection of these strange, ungainly, 
helpless-looking objects, which seem at times to stretch out clumsy arms appealingly to the 
traveler, and which one can not see on its native desert without unconsciously associating it with 
the uncouth forms of vegetation peculiar to the Carboniferous Era. 

Another large and very striking cactus found in this vicinity is called "pitahaya'' by the 
Mexicans, who esteem it very highly for its most palatable fruit. It consists of a cluster of 
incurving stems, several inches in diameter and 10 or 15 feet in height, which are covered with 
coarse, hair-like spines. 

All the hills and mountaius iu this vicinity are covered with a thick growth of "cholla" 
cactus, the needle-like spines of which readily penetrated shoes, leggings, and clothing, and caused 
much pain and annoyance to the working parties. 

From the Sierra de Sonoyta the line runs along the north slope of the Sonoyta Valley and 
then passes over the barren, cactus-covered ridges which lie between the Quitobaquita Mountaius 
and the Cerro Salado and separate the Sonoyta Valley from the dreaded Tule Desert. 

When the surveying party was working in this vicinity during the month of June, 1893, the 
heat was intense, the maximum temperature in the shade reaching 118° F. and the mean maximum 
in the shade for the whole month of June averaging 110^ F. The standard thermometer used was 
not graduated sufficiently high to give the temperature in the sun after 8 or 9 o'clock a. m., at 



24 UNITED STATES AND MEXICAN BOUNDARY. 

which time it ranged from 130° to 140° F. ; the temperature in the shade at this time generally 
ranging from 95° to 105° F.. a ratio which would seem to indicate an average maximum sunshine 
temperature during June of about 150° F. The temperature during June, 1893, must be considered, 
however, as in excess of the average, for a thermometer record kept at Sonoyta and covering a 
period of several years showed this to have been the hottest June during the period covered by 
the observations. 

At times the breeze which had swept over the scorching sands to the south was so hot as to 
wither vegetation and burn the skin as would the heat from a furnace, rendering it necessary, even 
when in the shade, to screen the face from its scorching heat. 

Leaving the divide north of the Oerro Salado the line strikes the Tule Desert, a wide, 
waterless area dotted with extinct volcanoes and numerous bare, isolated peaks of black or 
dark-brown igneous rocks, which but add to the loneliness and desolation of the scene. 

About tlie middle of this desert is a broad, low depression called "Las Playas,'' which is 
bordered by a fringe of mesquite and greasewood, and in which a few "charcos," or natural 
water holes, retain water for a short while after the occasional rains. West of this depression is 
a considerable area covered with lava from one of the extinct volcanoes in the vicinity. Near the 
road in this vicinity is the skeleton of a camel, which, the Mexican guide stated with much relish, 
had been brought for use on the deserts in northern Sonora and had perished here of thirst. 

Many miles to the south of the line the view is cut off by ridges of drifting sand, while to the 
north it is limited by jagged, rocky ranges, among the most prominent of which is the Sierra 
Pinta, a bare, rocky sierra, one-half of which is light gray while the other half is reddish brown. 

Between the Sonoyta A'alley and the Colorado Eiver the vegetation consists almost entirely 
of palo verde, palo fierro, mesquite, greasewood, and giant cactus, while the only grass seen is a 
tall, uninviting-looking species, called "galleta" by the Mexicans, which mules and horses ate 
with avidity and which is sufficiently plentiful, when one becomes familiar with the localities 
where it grows, to supply the place of hay, were it not for the fact that the scarcity of water 
ordinarily renders it impossible for travelers to delay long enough to permit their animals to 
graze. 

Leaving the Tule Desert the line crosses in succession the Sierra del Tule, the Lechuguilla 
Desert, the north end of the Sierra Lechuguilla, and the south end of the Sierra de las Tinajas 
Altas — the name by which this portion of the Gila Eange is known. 

The three sierras enumerated above present to the eye much the same general appearance, 
although dift'ering greatly from all other mountains encountered heretofore. They are bare, 
desolate, rough, and jagged to an unusual degree, and so steep that in many places it is impossible 
to climb to the summit, while in most places it is both arduous and dangerous; and when the 
jagged, knife-like crest is finally reached it often proves to be so narrow that it is impossible either 
to walk along it or set up an instrument there. 

All three of these ranges rise directly out of the surrounding desert and appear to be crests 
of mighty ranges whose foothills and lower slopes lie buried far beneath the drift and sand. The 
Sierra del Tule and the Sierra Lechuguilla are composed of a bewildering chaos of trachyte, 
porphyry, granitic rock, and lava, while the Sierra de las Tinajas Altas is composed of a coarse, 
grayish rock resembling granite, which appears at one time to have been washed by water, and 
as a consequence has been worn smooth and indented with numerous cavities similar to those 
found in rocks on the seashore. A few miles north of the boundary, in the Sierra del Tule, are 
several peaks of gray rock curiously capped with black trap or lava, one of which, called the Cerro 
de la Cabeza Prieta, is a very i)rominent landmark when crossing the Tule Desert. An extinct 
volcano, whose sides are curiously streaked with black lava, is situated on the west side of the 
Sierra del Tule, about 3 miles north of the wagon road, and the entire country south of this 
volcano is covered with a mass of broken, black lava. 

During the "early sixties" there was a large influx of Mexicans from Sonora to the gold 
diggings on the Colorado River, and an enterprising Mexican dug two wells near the road, in the 
Tule Mountains, built a small adobe house, and occupied it with his family for two years, for the 
purpose of selling water to travelers. But the deaths from thirst along this route became so 
frequent that the road was soon abandoned, and for over twenty years had remained unused. 



■I%i 




UNITED STATES AND MEXICAN BOUNDARY. 25 

Having accidentally learned of the former existence of these old wells, which are not shown on 
any maps, arrangements were made to have them cleaned ont as soon as possible. This was done 
by a party of Mexicans and Papagos fi'om Sonoyta, who found them almost tilled up., 

These important wells are situated on the road about 5 miles north of the point where the 
line crosses the summit of the Sierra del Tule, and when thoroughly cleaned out yield a supply of 
about 500 gallons per day. The water is beautifully clear, but owing to the presence of minerals 
has a vile taste and is very unwholesome. Near the wells stand the ruins of the old adobe house, 
the only building between Quitobaquita and the Colorado Eiver. 

About 6 miles northwest of these wells and about one-fourth of a mile east of the summit of 
the Cerro de la Cabeza Prieta, in a deep, rocky canon, are a number of natural tanks, worn in the 
rocks and filled by the rains. These tanks when full contain about 5,000 gallons of water, all of 
which is seldom exhausted, by evaporation alone, before another rain tills them. Tliese tanks are 
known as the "Tinajas del Cerro de la Cabeza Prieta," but were never much used by travelers, as 
they were off the road and could not be reached by vehicles. 

Many years ago the Papagos were accustomed to camp at these tinajas and the Tinajas Altas 
for the purpose of hunting "big horns" or mountain sheep, which then, as now, constituted the 
principal inhabitants of these desolate sierras. In the vicinity of the tanks are still seen the 
remains of their old camps, around which are strewn the horns of the mountain sheep — as many 
as twenty or thirty pairs having been counted at a single camp. 

This noble game is still plentiful in these mountains, fortunately protected by their ruggedness, 
their inaccessibility, the deserts which surround them, and tlie risk of death from thirst to which 
hunters would subject themselves. 

In the side of a natural, semicircular amphitheater on the east side of the Sierra de las Tinajas 
Altas, about 3.^ miles north of the boundary line, are the Tinajas Altas, a series of beautifully 
picturesque, natural tanks, worn in the solid rock by the waters of a narrow, rocky valley several 
hundred feet above, which, during the infrequent rains, come tumbling down the narrow gorge on 
the west side of the amphitheater and fill the tanks. These tanks hold about 15,000 or 20,000 
gallons in all, when tilled. They consist of seven large ones and a number of small ones; but with 
the exception of the lowest tank, which can be approached by animals, they are very difficult of 
access. The next three are reached with difiSculty by climbing the steep, water-worn rocks on the 
left of the gorge, but the upper ones can only be reached by ascending, to a height of several 
hundred feet, the stee]) ravine on the right of the gorge. To render this water available for the 
uses of the survey it was siphoned from the upper tanks to the lower one by a suitable length of 
hose. The water, although sometimes covered with a green scum, is deliciously cool and palatable. 
Unless consumed by prospectors or smugglers, which is seldom the case, water can be found at all 
times in some of these tanks, as there is no loss from seepage, and as the steep, rocky surrounding 
and overhanging walls greatly retard evaporation ; to what extent is shown by the fact that on 
the reconnoissance from Yuma to Quitobaquita in the winter of 1893 these tanks were found nearly 
half full, although the rainfall at Yuma for the preceding twelve months had aggregated less than 
three-fourths of an inch, a remarkable deficiency even for this dry section. That this water 
supply was a very uncertain one when the road from Sonoyta to Yuma was much traveled (as was 
the case during the rush to California in " the tifties " and to the Colorado Eiver diggings in " the 
sixties") becomes painfully apparent from the number of graves, about fifty in all, on the bluff 
just east of the tanks. These graves, covered by stones laid on the ground in the form of a cross, 
mark the resting jjlace of thirsty travelers who had pushed on to the tanks, hoping to find water 
there; but disappointed in this, and too weak to journey on, had perished miserably of thirst; 
their sufferings aggravated in many cases by the knowledge that the water which they craved 
could be obtained in one of the tanks but a few yards above them, had they but strength to 
climb to it. 

Although these tanks are now but little known, few Americans having ever visited them, yet 
it is very interesting to note that they are shown on the map made by Father Kino, the Jesuit 
missionary, of the region around the Gila and the Gulf of California, as the result of his travels 
from 1698 to 1701. 

S. Doc. 21:7 G 



26 UNITED STATES AND MEXICAN BOUNDARY. 

Two other tanks, of which do previous knowledge had been obtained, were discovered a short 
distance above the heads of the two valleys which indent the east side of tlie uionntains between 
1 and 2 miles north of the boundary. These had each a capacity of about GOO or 800 gallons. 

The road from Sonoyta to Yuma passes by Agua Dulce, Agua Salada, Tule Wells, and the 
Tinajas Altas, from which point it keeps on the east side of the mountain range and parallel to it 
to the valley of the Gila, down the south side of which it passes until the town of Yuma is reached. 
In "the fifties" the road forked about a mile north of the Tinajas Altas, the west fork going- 
through the pass at this i)oint, and thence directly over the Yuma Desert to the town of Yuma. 
This part of the route, however, was soon abandoned on account of the heavy sand and the loss 
of life from thirst. The road between Agua Dulce and Yuma is for the most part very heavy, and, 
until the Tule Wells were reopened, no certain supply of water could be counted on between Agua 
Dulce and the Colorado Eiver. This road is appropriately called by the Mexicans " El camino 
del Diablo." When traveling it for the first time, alone or with but few companions, it is hard to 
imagine a more desolate or depressing ride. Mile after mile the journey stretches through this 
land of "silence, solitude, and sunshine," with little to distract the eye from the awful surrounding 
dreariness and desolation except the bleaching skeletons of horses and the painfully frequent 
crosses which mark the graves of those who perished of thirst — grim and suggestive reminders 
when the traveler's supply of water is running low. In a single day's ride sixty-five of these 
graves were counted by the roadside, one containing an entire family, whose horses gave out and 
who, unable to cross the scorching desert on foot, all perished together of thirst. Their bodies 
were found by some travelers during the following rainy season, and were all buried in one grave, 
which is covered with a cross of stones and surrounded with a large circle of stones, inside of 
which not a bush nor a blade of grass grows. Near by lie the skeletons of their horses and the 
broken fragments of their water bottles. 

During the few years that this road was much traveled, over 400 persons were said to have 
perished of thirst between Sonoyta and Yuma, a record probably without a parallel in North 
America. 

Leaving the Sierra de las Tinajas Altas the line crosses the Yuma Desert and descends into 
the valley of the Colorado, terminating at the point where it intersects the axis of the channel of 
that river. 

The name Y'uma Desert is applied to the entire country included between the Gila Eiver, the 
Gila Range, the Gulf of California, and the Colorado River, a region without water and covered 
for the most part with shifting sands and a scrubby growth of greasewood. I'arallel to the Gila 
Range and separated from it by a valley 4 or 5 miles in width is a range of hills which begins 
about a mile or two north of the line and extends northwest for a distance of 15 or 20 miles. 

About halfway across the desert the line crosses a ridge of drifting sand 2 or 3 miles in 
width and then a low, volcanic ridge which borders it on the west. Many miles to the south is 
seen a perfect sea of sand out of which rise jagged, isolated peaks and extinct volcanoes. Every- 
where else is an endless succession of sandy swells and hollows sloping gradually down to the 
Colorado River. Descending abruptly from the desert the line passes over the fertile valley 
of the Colorado and terminates in the channel of that stream. 

Section 5, Colorado River. — The Colorado, like the Rio Grande, is a variable stream, carrying 
an immense amount of sediment, and is generally navigable by light-draft steamers throughout 
the year for several hundred miles above its mouth. The river floods in June, during which time 
great changes of channel take place in those reaches, which, like the boundary section, are 
bordered by alluvial banks. The river valley along this section is many miles in width and is 
covered with a dense growth of mesquite, cottonwood, willow, arrowwood, (juelite, and wild hemp. 
The soil is exceedingly fertile from the frequent inundations, and would doubtless produce fine 
crops. 

The Colorado Eiver along the boundary is peculiar in that its course does not follow the 
lowest depression between the Gila Range and the Coast Range, but lies some 50 or 60 miles east 
of this depression, and at an elevation of over a hundred feet above it. Nor does it seem, as is 
sometimes contended, that this elevation is due entirely to the constant deposition of sediment 
along its banks and the consequent elevation of its bed, for tlie profile along the boundary over 



UNITED STATES AND MEXICAN BOUNDARY. 27 

the Colorado Desert, west of Yuma, shows the same gradual and uniform downward slope, until 
the depression at Salton River is reached, and on this desert no alluvial sediment appears ever to 
have been deposited either in recent or past ages. Moreover, in slope, elevation, and composition, 
this desert appears but a continuation of that on the east side of the valley. 

This river is also remarkable for the very high tides at its mouth, and for the "bores" which 
at certain phases of the moon come rushing up the tidal portion of the stream, threatening with 
destruction all small craft encountered. 

At the junction of the Gila and Colorado is located the Jiourisliing little town of Yuma, which 
before the advent of the Southern Pacific Eailway furnished supplies for almost all of Arizona and 
Xew Mexico. The town still supplies the mining camps on the Colorado Eiver and its vicinity, 
and has become quite a resort for persons afflicted with pulmonarj^ troubles. Extensive projects 
for irrigating and cultivating the fertile lands of the Colorado River Valley and vicinity are now 
being promoted, but up to the present time practically none of this land is cultivated, except by 
Indians. 

The river valley from Y'uma to the gulf is inhabited only by Yuma, Co-co-pah, and Diegeno 
Indians, peaceable and light-hearted people, fond of games, excellent swimmers, and delighting, 
like all savages, in painting their faces and bodies. The men are noticeable for their splendid 
physique, but the women are generally fat and unattractive in appearance. As a rule they 
possess no firearms, and on the lower reaches of the river may yet be seen hunting with the bow 
and arrow. They still cremate their dead, frequently burning at the same time the rude hut 
and personal effects of the deceased. 

Section 6, azimuth line from the Colorado Firer to the Pacific Ocean. — Starting at the Colorado 
River, the line x^asses for about two-thirds of a mile over the fertile river valley, then rises to the 
water-washed mesa southeast of Pilot Knob, a prominent, isolated mountain about a mile north 
of the line. Over this mesa the line passes for about 3 miles, when it encoianters several high 
ridges of drifting sand, all of which it crosses in a distance of about 4 miles. 

From the sand hills to Salton Eiver, a distance of about 27 miles, the line passes over a flat 
desert, similar in ai^peai'ance and vegetation to the Y'uma Desert, and forming a part of the 
Colorado Desert, the name which is applied to the entire country included between the mountains 
north of the Southern Pacific Railway, the Colorado River, the Gulf of California, and the Coast 
Range. From Salton River to a point a little over a mile east of the north spur of Signal Moun- 
tain, a distance of about 21 miles, the line passes over an alluvial depression, a considerable portion 
of which is covered at intervals of several years by the overflow from the Salton and i^ew rivers, 
as was the case in the summer of 1891, when their overflow filled the dry bed of the Salton Sea, 
and for a time threatened to submerge the tracks of the Southern Pacific Railway in this vicinity. 

To understand the nature and cause of these overflows it is necessary to describe somewhat in 
detail the topography of this region for a considerable distance on both sides of the boundary line. 

About 5 miles below the boundary the Rio Padrones, a branch of the Colorado, ordinarily 
about 75 feet in width, and having a very swift current, separates from the main stream and flows 
in a generally southwest direction, emptying into a lake several miles in length, called Jululu 
Lake. 

This lake lies some 15 or 20 miles south of tlie boundary line, and near its west shore are the 
famous mud volcanoes of the Colorado Desert, while a short distance west of these loom up the bare, 
rocky ridges of the Co-co-pah Mountains. The outlet of this lake, known as Hardys River, flows 
in a generally southeast direction, and unites with the Colorado some 20 miles above its mouth. 

The area included between the Colorado and these western branches is intersected by numer- 
ous " blind channels," which are all filled when the Colorado overflows. 

At times of extraordinarily high water in that river another channel, which branches from the 
Colorado in the same locality as does the Rio Padrones, becomes filled, and under the name of 
Salton River flows west for about 30 miles, then northwest for about 50 miles, antl empties into 
the depression called Salton Sea. At the same time Jululu Lake becomes so filled from the over- 
flow that a portion of its waters seeks an outlet by a channel called Xew Eiver, which flows in a 
northwest direction for about GO miles, and also empties into Salton Sea. When the flood in the 
Colorado subsides these streams cease to flow, aud their courses are marked by a succession of 



28 UNITED STATES AND MEXICAN BOUNDARY. 

lagoons remaining in the deep channels which their waters have cut in the alluvial soil. Exposed 
to the dry atmosphere of the desert, these lagoons soon evaporate, and for years at a time not a 
drop of water can be found along their courses. 

Ordinarily the height and duration of the flood in the Colorado barely suffices to fill Salton 
and New rivers for a short distance from their sources, and it is only at long intervals that any 
part of the waters of these streams reaches Salton Sea. This, however, occurred in 1801, when 
not only were these rivers tilled, but so great was the volume of water poured into them that they 
in turn overflowed their banks and submerged much of the surrounding country, the overflow of 
the two rivers, which in the limits of the United States are approximately parallel to one another, 
in some cases uniting. The channels of these streams are fringed with a thick growth of mesquite, 
while the limits of overflow are plainly marked by a most luxuriant growth of an Amaranthus 
(called "quelite" by the Mexicans), a plant much esteemed as food for cattle. 

The growth of qnelite, mesquite, and grass following the overflow of 1891 furnished fine 
pasturage for several thousand head of cattle brought here from the overstocked ranges of Arizona 
and California. 

The entire area between the head of Salton Sea and the Gulf of California once undoubtedly 
formed a part of this gulf, from which in comparatively recent geological times its waters were 
separated by some process still somewhat obscure. 

By many it is believed that this separation was effected by an elevation or upheaval in the 
region between the boundary line and the present head of the gulf. 

While admitting that this theory is perfectly plausible and quite possibly correct, j'et from 
the present condition of things it seems more probable that this separation was effected by the 
deposition of sediment from the Colorado liiver, aided perhaps by the action of the winds and 
tides on this sediment. 

From the configuration of the surrounding country it would ap])ear that before this separation 
occurred the Colorado lliver must have flowed into the gulf on its east shore about 75 or 100 miles 
below its then head and at a point where the gulf must have been quite narrow, limited as it was 
by a spur of the Co-co-pah Mountains on the west and by the Yuma Desert on the east. 

When we consider the immense amount of sediment brought down by the waters of the 
Colorado, and the further fact that rivers emptying into the sea invariably discharge their waters 
at right angles to the shore line, in this case directly across the narrow gulf, it does not seem 
improbable that in time this sediment would separate the waters above the mouth of the river 
from those below. If this theory is correct, the original bottom of the gulf would be found only in 
the vicinity of Salton Sea, which is about 250 or 275 feet below mean sea level, while from that 
point to Jululu Lake would be found a gradually increasing thickness of sedimentary deposit from 
the overflows, first, of the Colorado and afterwards of Salton and New rivers. 

To the north of Salton Sea the old beach line is easily traced, and its elevation differs but 
little, if any, from that of the Pacific, showing that if any elevation or dei)ression has occurred 
elsewhere, this locality at least has been practically unaffected thereby. 

Salton and New rivers present the anomalous condition of two streams parallel to one another, 
and to the axis of lowest dep^-ession in their vicinity, the first being about 18 and the second about 
8 miles east of this axis, as measured along the boundary. The corresponding elevations of the 
surface at each point being +20', — 7', and — KJ' respectively, referred to mean sea level; the last 
marking the lowest point along the entire boundary line. About 4 miles west of this ]ioint the 
line crosses the foot of the north spur of Signal Mountain, a iiromineut peak marking the north 
end of the Co-co-pah Eange, and visible from all points of the Colorado Desert. For about 10 
miles the line passes over a bare, rocky, water-washed mesa, about 300 feet above sea level, from 
which, by a succession of three or four terraces, indescribably bare, jagged, rough, and precipitous, 
the line, in a distance of about 11 miles attains the summit of the Coast Range at an elevation of 
about 4,500 feet. 

This range acts as an effectual barrier in shutting off from the Colorado Desert the moisture- 
laden winds of the Pacific. This action was beautifully shown in March, 1893, when for three 
days it had been raining almost continually over the entire country west of tlie summit, several 
inches of rain having fallen in that time. Daring this entire period a gale from tlie coast was 



UNITED STATES AND MEXICAN BOUNDARY. 29 

driving a continual mass of dark rain clouds over the crest of the Coast Range, where at the time 
it was alternately raining and snowing. Encountering the hot air rising from the desert these 
clouds rapidly began to dissipate, and finally disappeared entirely about 10 miles east of the 
summit, appearing when viewed from below like a vast cloud of steam exhausted into air. 

Between the Co-co-pah Mountains and the Coast Range, and about 10 or 15 miles south of the 
boundary, is a large salt lake, called Lake Maquata by the Indians, and about 9 miles east of the 
summit of the Coast Range and about 5 miles south of the boundary, in the mouth of a large 
caiion, is a small stream of pure mountain water. 

During the years when New and Salton rivers remain dry no water is found near the boundary 
line between the valley of the Colorado River and Coyote Well, a very shallow well of wretched- 
tasting water, about 8 miles north of the boundary and about 12 miles east of the summit' of the 
Coast Range. The entire Colorado Desert is subject to frequent sand storms and constant and 
violent winds prevail along the foot of the Coast Range. The summer heat is fearful; the highest 
temperature ever recorded at any Weather Bureau Station in the United States, 128° F. in the 
shade, having been obtained in July, 1S87, at IMammoth Tank, a station on this desert about 25 
miles north of the boundary. Although far less traveled than before the advent of the railroad, 
the desert continues to claim its victims, over half a dozen persons having perished of thirst on it 
during the past two years. 

From the summit of the Coast Range to the Pacific, settlements become more frequent; the 
country is better known, and the maps more accurate; consequently less detail is necessary in 
describing it. 

The descent from the summit to the Pacific is far more gradual than that to the Colorado 
Desert and the entire character of the vegetation undergoes an abrupt change; the mountains 
being covered with a dense growth of brush, while the valleys are dotted with beautiful evergreen 
oaks. 

Leaving the summit of the Coast Range, the line crosses the Jacumba Valley and the broken 
country west of it, and passes just to the south of Round Mountain; thence it crosses succes- 
sively the rocky ridges west of Round Mountain, Milquata Valley, another succession of ridges, 
Tecate Valley, and Mount Tecate, passing over the south slope of this mountain at an elevation 
of about 3,400 feet. 

Leaving Mount Tecate, the line crosses Cottonwood Creek, the south slope of Otay Mountain, 
at an elevation of a little less than 1,700 feet, Otay mesa, Tijuana River, and the high, flat ridges 
in the vicinity of the ocean. 

For many years previous to the completion of the Southern Pacific Railway a stage line had 
been maintained between Yuma and San Diego; wells had been sunk in many places on the 
desert, and stage stations established in their vicinity. At the time of the survey this road had 
remained untraveled for years; the wells had all filled up; the station houses were but ruins, and 
all traces of the old road were in many places obliterated for miles at a stretch. Although still 
known by their old names, the stations now afford neither a permanent water supply nor shelter. 
The road used on the survey followed the old stage route along the Colorado and Salton River 
valleys, via Hanlons, Cooks AVells, and Seven Wells, until Gardners Station was reached. 

From this point to JSTew River station the old road had been washed out by the overflow of 
1891, and consequently it was necessary to continue down the Salton River Valley for several miles 
and then ascend to the sandy desert on the north, on which the road continued for a few miles, 
descending into Saltou River Valley and crossing the dry bed of that river about a mile below the 
boundary. From this point the road continues to Indian Wells, crossing the boundary line about 
3 miles east of New River, and uniting with the old stage road a short distance east of Indian 
Wells just after crossing the dry bed of New River. 

From Indian Wells to San Diego the road follows the old stage route, via Laguna Station, 
Coyote Well, Mountain Spring, Jacumba, Campo, Potrero, and Dul/Ai-a. Between Cooks Wells 
and the point where it crosses Salton River the road is very heavy. Just before reaching Mountain 
Spring Canon a stretch of very heavy sand is encountered, which continues up to the mouth of 
the cafion. The road through the caiion is rough beyond description, and although but 3 miles 
in length, caused more damage to vehicles than did any other road on the entire survey. 



30 UNITED STATES AND MEXICAN BOUNDARY. 

Witli these exceptions, tlie road is fair for the entire distance from Salton Eiver to San Diego. 
It must be borne in mind, however, that between the Colorado River and Jacumba Valley there is 
ordinarily not a blade of grass, while often for months at a time not a drop of water can be found 
between the Indian village, a few miles east of Cooks Wells, and Coyote Wells, a distance of 80 
miles by road. Twelve miles beyond Coyote Wells is Mountain Spring, attbrding a good supply 
of excellent water. 

The next water, a bold sulphur spring, is found about 8 miles farther, at Jacumba, the first 
settlement encountered after leaving the valley of the Colorado River. 

From this point to the Pacific, water is sufScieutly plentiful to render a detailed description 
of its location unnecessary. 

To persons unfamiliar with the deserts of the Southwest, it will doubtless appear that undue 
prominence has been given to the question of water in the preceding description of the country 
along the boundary, and in refutation of this idea it is necessary to call attention to the fact that 
supplying, the working parties with water on the deserts was the problem of the survey, in 
comparison with which all other obstacles sank into insignificance. To the traveler on the 
desert the all-important questions are: The distance to the next w-ater, the nature of the supply, 
and the character of the intervening roads. For while he may be able to live without food for 
several days, he knows that, exposed to the scorching heat of summer, men drinking their fill 
at sunrise frequently become crazed and in some cases perish of thirst before sunset. 

Nor must it be forgotten that at such times so profuse is perspiration and so rapid its evapora- 
tion that the quantity of water consumed by men and animals is very large, averaging at one 
period of the survey about 7 quarts per day for the men and 20 gallons for the animals. 

On the desert the mirage continually mocks the traveler with deceptions apparently so real 
that it is difiQcult to persuade liim that what he sees is a mere atmospheric freak and has no actual 
existence. 

Just before sunrise craggy peaks are seen, capped by similar, inverted peaks, which gradually 
become flatter and flatter, frequently stretching out like great arms from the summit and uniting 
•with those from neighboring peaks. Once a city with all its buildings appeared in a valley many 
miles to the north, but the morning sun (juickly resolved it into a number of large bowlders, near 
the foot of a craggy mountain. 

At another time, on the flat, bare Yuma Desert, the reconnoissance party seemed to be in a 
level depression, surrounded on every side by a vertical, palisade-like wall of solid rock, 50 or 100 
feet in iieight, which moved with them as they journeyed toward the river, but gradually diminished 
in height until it finally disappeared. 

The most common deception, however, is seen in the heat of the day, when beautiful, quiet 
lakes and timber-fringed ponds lie in tantalizing attractiveness, apparently but a few hundred yards 
away, the details so perfect that the reflection of every object on the bank is faithfully reproduced, 
audit is little wonder that thirsty travelers unaccustomed to this mirage are lured from the road to 
procure this water, which ever appears but a little distance ahead, yet is never reached. 

It was also in the heat of the day that distortions of the size and form of animals generally 
occurred; as in one case where a band of wild horses was mistaken for a herd of antelope, and 
followed for several miles as such before the mistake was discoveied; and in another, where a 
coyote was mistaken for the same animal. At times a jack rabbit would loom up on the desert 
with the apparent size of a cow, while occasionally the legs of animals would be so comically 
lengthened as to give them the appearance of being mounted on stilts many feet in height. 

BECONNOISSANCES. 

Owing to the fact that a considerable portion of the country lying along the international 
boundary is of a character little calculated to invite travel by white persons, it was impossible to 
secure in advance reliable information concerning water, roads, and the general topographical 
features of the country, which information was essential to a proper prosecution of the survey. 

To obtain this information mounted reconuoissances were made from time to time as required 
by the progress of the work. 

With the exception of a reconnoissance of about 100 miles made by Mr. J. L. Tan Ornum, 
assistant engineer in charge of the topographic party (who also formed one of the reconnoissance 



UNITED STATES AND MEXICAN BOUNDARY. 31 

party on three other occasions when the aggregate distance covered was about 700 miles), these 
reconuoissances were made by Lieut. D. D. Gaillard, United States Corps of Engineers, with a 
party comprising from two to five persons in all. . 

Pack mules were used to carry supplies whenever the character of the couiitry was such as to 
render the use of a spring wagon impracticable. 

The total distance covered on the recounoissances was 2,134 miles — 2,008 miles on horseback 
and 126 miles on foot. 

The time occupied in making a single reconnoissance varied from one to fourteen days, and 
the corresponding distances from 24 to 413 miles. 

The usual discomforts incident to such exiieditions were experienced and were aggravated, in 
the case of recounoissances on the desert, by the intense heat and the scarcity and poor quality 
of the drinking water. 

On a reconnoissance of 301 miles, made June 2-11, 1893, the maximum thermometer reading 
in the shade each day varied from 105° to 118° F. The discomfort of the trip was further increased 
by the ftict that the first four watering places were 45, 40, and 50 miles apart, respectively. 

In many cases there was little or no grazing for the animals, and as it was impossible to pack 
enough hay to last them for the entire trip they had to be fed principally on barley, and were 
often without water for considerable periods — on one occasion for a period of forty hours. 

Yet in spite of privations it is pleasant to be able to record the fact that not a man nor an 
animal was injured or disabled on any of these expeditions. 

CHAPTER III. 

ASTRONOMY. 

On the organization of the International Boundary Commission at Juarez, Mexico, November 
17, 1801, the members of the Mexican section were present with a full outfit of instruments and 
observers ready for work. 

These instruments had been purchased by the Mexican Government at the date of the first 
convention in 1SS2, and were used by them to determine the latitude and longitude of Juarez at 
that time while waiting for the United States Government to appoint a commission. 

The United States commissioners having reached El Paso without instruments, men, or 
transportation, it was necessary for them to return north to organize their party, engage assistants, 
procure instruments, and purchase animals, wagons, and camp equipage before they would be 
able to begin field operations. 

The time between December 1, 1891, and January 20, 1892, was spent in securing assistants 
and in organizing the transportation for the field parties. 

Instruments used. — The question of the proper instruments to use for the observations of 
latitude, azimuth, time, and magnetics received careful consideration. 

The time was too limited to have new zenith telescopes of improved ijatteru constructed, and 
as the old Wurdemanns used in the survey of the northwestern boundary in 1872-1876 were 
stored at the engineer depot at Willets Point, N. Y., a requisition was made for the following 
astronomical instruments in addition to barometers, surveyors' transits, etc., for the topographical 
work of the survey: Two Wurdemann zenith telescopes, Nos. 18 and 20; two sextants and 
artificial horizons; two mean time chronometers; two sidereal chronometers. 

The two zenith telescopes were completely overhauled and were partially reconstructed by 
Fauth & Co., of Washington. In the field operations but one of them was actually used, the 
other being held in reserve. Each was furnished with spare level-tubes in case of accident to 
those attached to the instruments. 

For azimuth observations a 10-inch repeating theodolite, reading to 5 seconds on horizontal 
limb, was made by Fauth & Co., having an eyepiece micrometer and high standards for supporting 
the telescope, enabling the telescope to be " transited through " for reversal instead of being lifted 
from the wyes. This instrument was used for azimuth observations, using the liiethod of measuring 
by micrometer the angles between the star near elongation and the mark. The high standards, 
constructed of aluminum, were of great service in the field iu running lines on the ground, while 



32 UNITED STATES? AND MEXICAN BOUNDARY. 

the micrometer in the eye end, together with the use of signals by heliotrope, facilitated the placing 
of the forwai'd signal quickly in line with the back signal. 

Micrometer readings on both back and forward signals afterward determined the small 
correction to be applied to the place of the forward signal. 

Two direction theodolites of 8-iucli limbs reading by two micrometer microscopes to single 
seconds were purchased from Fauth & Co., in January, 1803, and were used in measuring the 
angles of the triangulations made at Nogales and Yuma. These theodolites were made with low 
standards and telescopes of high power. 

One 8-inch repeating theodolite or altazimuth was borrowed from the United States Coast and 
Geodetic Survey for the magnetic observations, and was used along the parallels of 31" 47' and 
31° 20', after which it was returned, at the request of the Superintendent, to the Coast Survey 
office, being needed in Alaska. This instrument was wholly of bronze and brass, no steel or iron 
being used. The telescope was fitted with an eyepiece micrometer and could be used for latitude 
observations instead of a zenith telescope, and it carried above the telescope a box containing a 
6-inch needle for measuring the magnetic declination. 

The sextants and artificial horizons were used for time observations. Observations of the 
sun's altitude were made in forenoon and afternoon, and the resulting errors of chronometers were 
sufficiently accurate for use in latitude and azimuth observations. 

The four chronometers were put in complete order by Negus & Co., of New York. For trans- 
portation each chronometer was inclosed in a leather case, and two of these cases were then 
inclosed in a well-padded wooden box. This box was then inclosed in an outer wooden box 
having a false inside cover and bottom, backed by a system of spiral springs to deaden jars. The 
chronometers were kept in these double boxes from the time of leaving New York to the end of 
the work at San Diego, except the chronometers used for astronomical observations, which were 
immediately returned to the boxes after the observations were finished. 

This method of packing the chronometers was very satisfactory in its results, no injury to 
any chronometer having occurred, although transported many hundred miles over a very rough 
country with no roads, and the temperature of the chronometers changed very slowly, although 
the usual viiriation in the outside temperature during the twenty-four hours was from 50° to 70°. 

For a detailed description of all these instruments see report of John F. Hayford, assistant 
astronomer. 

Zenith telescope No. 20 was used for all the latitude observations and No. IS held in reserve 
in case of accident to the former. 

The mounting of the zenith telescope and theodolite under one cover, so as to combine stability 
of foundation with portability, was the subject of considerable study and experiment. An observ- 
atory of some sort was required, and it needed a floor. This observatory must be used also as an 
office for the astronomical party during the day in which to do the necessary computing and 
writing, none of our tents being large enough for this purpose. The whole must be portable and 
composed of parts small enough to load readily on a wagon. 

Both the zenith telescope used for latitude and the theodolite used for azimuth observations 
were mounted on hollow, triangular wooden piers 5 feet long, hooped with iron, painted, and sunk 
like fence posts, after which the triangular inside was filled with earth well rammed. A floor of 
boards, 9 by 12 feet, made in six sections and to fit around the wooden piers, supported only at 
the four corners, was laid, on which was erected a tent in the form of a " lean-to shed," with roof 
sloping toward the north, and o])enings the whole length of the roof over each instrument. The 
sides and roof of the tent were suijported and stiffened by a framework of wood and held in place 
by rope guys at corners and sides. 

The hollow wooden piers were very satisfactory and proved as firm as masonry. At Nogales 
and Yuma the zenith telescope was mounted on the brick piers used by the United States Coast 
and Geodetic Survey longitude party, and at those places the observatories were of wood. A 
comparison of the results obtained at these stations with those where the wooden piers and tent 
were used were all in favor of the latter. The instrument changed less in level during the night 
when mounted on the wooden pier, and the temperature inside the tent was more nearly the same 
as the outside air. The usual difference was 1° C. only, which rendered the stars observed very 
steady. 



UNITED STATES AND MEXICAN BOUNDAEY. 



33 



LONGITT'DES. 

The original plan agreed on by the joint commission for running the boundary was to determine 
both the latitude and longitude of the extremities and turning points of the boundary, at or near 
which points the monuments erected by Emory were reported as still standing, and to observe for 
latitude and azimuth on the parallels at points about 20 miles apart. 

Dr. T. (J. Mendenhall, Superintendent United States Coast and Geodetic Survey, at the request 
of the State Department, detailed a party to determine the longitude of five points, viz: El Paso, 
the monument at the intersection of parallel 31° 47' with the meridian, Kogales, Yuma, and old 
Monument Xo. 1 on the Pacific, near San Diego. The field work was completed between January 
and June, 1892. 

The method used was exchange of signals by telegraph. Usually ten nights' exchanges were 
obtained, five with one observer at eastern station and the other at western, then five more with 
the positions of the observers reversed. The same stars were observed at both stations for time 
and instriimental con-ection to eliminate errors in the right ascensions of the stars used. 

Assistants 0. H. Sinclair and G. li. Putnam had charge of the longitude parties, and the field 
expenses of both parties were paid by the United States section of the Boundary Commission, but 
no salaries to either officer. 

The longitude of Monument No. 1, where the parallel of 31° 47' leaves the Eio Grande, was 
fixed by a triangulation connecting the monument with the longitude station at El Paso. The 
longitude of monument 40 at the intersection of parallel 31° 47' with meridian was obtained 
directly by using a temporary field telegraph line erected by direction of General Greeley, Chief 
Signal Officer, United States Army, connecting with the Western Union telegraph line at Separ, 
on the Southern Pacific Eailway. General Greeley also furnished operators at both ends. 

The line was very quickly and successfully erected under direction of Lieut. Prank Greene, 
signal officer. Department of Arizona, by a detachment from the Twenty-fourth Infantry under 
command of MaJ. .James N. Morgan, to whom we are indebted for the prompt and successful 
completion of the work. 

The longitude of Nogales was transferred to monument No. 127, at the intersection of parallel 
31° 20' with the one hundred and eleventh meridian, as determined by Emory, by a triangulation 
connecting the monument with the longitude station at Nogales. The longitude of monument 
No. 204, 20 miles below Yuma, on the line connecting monument No. 127 with the initial point in 
the Colorado, was obtained from the observed longitude at Yuma by triangulation. The longitude 
of monument No. 207, where the line from the junction of the Gila and Colorado leaves the river, 
was obtained from the same triangulation. The longitude of monument No. 258, on the Pacific, 
was furnished by the Coast and Geodetic Survey, based on observations for longitude made at San 
Diego in 1892, connecting this point with the main chain of longitude stations on the Pacific Coast 
and reduced to the monument by Coast and Geodetic Survey triangulation. 

lleaults for difference of longitude by United States Coast and Geodetic Survey of points on Mexican boundary. 
SAN DIEGO, CITY PARK, CAL., AND TUIIA, GOVERNMENT RESERVATION, ARIZ. 



Date. 


A K 


p. 




10 09. 162 
.095 
.087 
.100 
.130 
.144 

:: 

.112 
.130 
.152 


I 


March 16 1892 










Observers change stations : 


March 24 ISS' 




March 26 1892 







Weighted mean. 10" 09.H4'±O.UU5-. 

Transmission or vrai'e and armature time = 0.032- ±0.002'. 

Personal equation between C. H. Sinclair and G. R. Putnam, S — P = +0.192>±0.0M-. 



34 



UNITED STATES AND MEXICAN BOUNDARY. 



Results for difference of longitude iy United States Coast and Geodetic Survey of points on Mexican feoMndary— Continued. 
YUMA, GOVERNMENT RESERVATION, ARIZ., AND NOGALES, IN REAR OF CtTSTOil-HOUSE, ARIZ. 



April 13, 1892 

April 14, 1892 

Aprill5,1892 

April 16. 1892 

April 17, 1892 

Observers change 

April 19, 1892 

April 20, 1892 

April 21, 1892 

April 22, 1892 

Apra23,1892 



Weighted 

TransmiBSion or wave and ar 

Personal equation between C 



14" 43.690- ±0.007'. 

wave and armature time = 0.045'±0.003'. 

Sinclair and G. R. Putnam 



NOGALES, IN REAR OF CUSTOMHOUSE, ARIZ., AND EL : 



+0.150- ±0.005'. 
IN UNITED STATES RESERVATION, TEX. 



April 29, 1892 

April 30, 1892 

May 1,1892 

May 2,1892 

May 4,1892 

Observers change stations : 

May 6,1892 

May 7,1892 

May 8,1892 

May 9,1892 

May 10,1892 



"Weighted mean, 17" 48.520-±0.009'. 
Transmission or wave and armatare time^: 0.034'±0.001' 

Personal equation between C. H. Sinclair and G. R. Putnam, S — P = +0.126 ±0.004'. 
CORNER OF BOUNDARY, NEAR MONUMENT NO. 40, AND EL PASO, IN UNITED STATES RESERVATION, TEXAS 



Date. 


A A , p. 


May 14 1892 


6 52. 642 
.660 
594 






May 16 1892 













Weighted mean, 6" 52.626' + .013'. 

Transmission or wave 

Applied personal equation, S — P= + 0.126- ± 0.08". 

Absolute longitudes of the several positions can only be given after the final adjustment of the 
general longitude system of the United States has been made; at present but a very few Hues are 
wanting to complete the longitude net. Approximately we have: 





Time. 


Longitude. 




h.m. ,. 
7 05 57. 350 
7 12 49.976 
7 23 45.870 
7 38 29. 560 


106 29 20.25 
108 12 29. 64 
110 56 28. 05 
114 37 23.40 






Yuma 











UNITED STATES AND MEXICAN BOUNDARY. 35 

Tlie probable error of any of these results may be taken as ±0.12^ or i 1.80". We also bave 
the resulting value for the supposed Wheeler station at El Paso: Time, 7'' 05'" 50.7127": longitude, 
106O 29' 10.90". 

Longitude of pi-ominent points on boundary. 



Points. Longitude. 




o , „ 1 




106 28 55. 11 


Monument No. 1, Rio Grande 


106 3139.03 




108 12 29 67 








110 56 34. 63 




111 4 34.45 
114 46 48. 64 
114 43 54.31 
117 7 31.89 






MonumentXo 358 Pacific 





LATITUDES. 

All the observations for latitude were made with zenith telescope ^o. 20, by the method of 
micrometer measures of difference of zenith distance of pairs of stars near the zenith. The time 
for latitude and azimuth was obtained by sextant observations on the sun. 

As it -was necessary to have the results for latitude and azimuth for the use, of the tangent 
parties at each station without delay, and as no one catalogue would give the accurate places of a 
sufficient number of stars from which pairs could be selected to observe for latitude, arrangements 
were made, before leaving Washington, with Prof. T. H. Saffoid, of Williams College, to make 
selections for our use from the large number collected by him during many long years of labor, 
together with the latest publications available, and to furnish us with the mean declinations for 
1892 of stars properly located for observation along the boundary. 

By means of these lists of stars it was possible to observe as many pairs as were convenient 
on any one night, and to observe as many nights as were necessary to obtain a satisfactory result. 

Usually about 100 results for latitude were obtained, the number of pairs used varying from 
20 to 60, with a resulting probable error of from ±0.03" to ±0.05". 

The apparent places were computed for the actual dates of observation, and the final result 
for latitude of the station was obtained within three or four days from the time of the last 
observation. 

AZIMUTH. 

The observations for azimuth were made with theodolite No. 725, 10-inch Fauth. 

The method used was that described in Bulletin No. 21, United States Coast and Geodetic 
Survey, 1890, entitled " Determination of an azimuth from micrometric observations of a close 
circumpolar star near elongation, by means of a meridian or transit and equal altitude instrument, 
or by means of a theodolite with eyepiece micrometer.'' 

This method is capable of great accuracy of result, but demands that an elongation mark be 
set up in the direction of a vertical plane passing through a close circumpolar star when near 
elongation, and that an instrument with an eyepiece micrometer be available to measure 
micrometrically the angle between the vertical planes passing through the mark and star. By. 
this method a satisfactory result for azimuth for a night could be obtained in from thirty to fifty 
minutes; one set or result taking about ten minutes. 

The instrument was too small and light to obtain the best results, but three sets per night 
and three nights gave an azimuth with a probable error of result of less than ±0.3"; the probable 
error of a .single result was aboirt ±0.5". 

More than four sets on the same night were found to add nothing to the accuracy of the mean 
for that night, but several nights' observations were needed as the mean results of different 
nights differed frequently by a second or more. Mean range for 15 stations =^1.2". 

As the observations were made very near elongation — within half an hour — and on both sides 
of that epoch, but a portion of one turn of the micrometer was used, and any error in the assumed 
values of the micrometer or of the chronometer correction was nearly eliminated from the mean 
result of the night. 



36 UNITED STATES AND MEXICAN BOUNDARY. 

The atmospheric conditions were very favorable for both latitude and azimuth observations, 
the stars showing as bright points and very steady. The temperature of the observing tent 
rarely differed more than a degree froiA that of the outside atmosphere. 

All the observations for latitude, time, and azimuth were made by Assistant Astronomer John 
F. Hayford, and for a detailed description of the instruments used, method of observation and 
reduction, and for the results, see report of assistant astronomer hereto appended. 

Mr. James Page served as computer during the whole time devoted to astronomical observa- 
tions, and made all the astronomical computations, which were afterwards revised by Messrs. 
Hayford and Finley. 

Mr. H. B. Finley served as recorder for the astronomical party, recording all the astronomical 
observations, and in addition assisted in the measurement of horizontal angles for the triangulation. 

On the completion of the astronomical and triangulation observations at Yuma, Mr. John F. 
Hayford, assistant astronomer, and Mr. James Page, computer, were transferred to the party 
running the line between the Colorado River and monument 127, and Mr. H. B. Finley, recorder, 
to the party running the California line between the Colorado Biver and the Pacific. 

These gentlemen performed all their duties while with the astronomical party, often exposed 
to great hardship and discomfort, with zeal, energy, and intelligence. At several stations 
observations were continued throughout the entire night between sunset and sunrise, and 
during the days they were kei)t busy at the observation of time and magnetic declination, and in 
computing. Owing to lack of laborers, they worked also with pick and shovel to set the wooden 
piers and erect the astronomical tent to be ready for observations the night following the moving 
of observatory and camp from one station to another. 

The catalogue of stars furnished by Professor Safiford is herewith given in tabular form. 

In this catalogue the declinations are given to hundredths of a second, and have been revised 
by Professor Safiford since the latitude observations were made. The original declinations were 
given to tenths of a second only and used in computing the resulting latitudes. The column 
headed JS in the catalogue gives the correction to be applied to the catalogue declination to 
obtain the value used in comijuting the latitudes along the boundiiry. 

INTRODUCTION TO THE CATALOGUE. 

[By T. H. Sartbrcl.l 

This introduction is briefer than it would have been if I had not been taken suddenly and 
seriously ill when just completing the preparation for press. 

1. Selection of stars. — The pairs were selected for the stations with especial reference to avoid- 
ing doubtful positions. The proper motions are the doubtful element owing to deficiency of old 
authorities. The best pairs then are those contained in Auwers' Bradley, and also observed very 
lately. The rejected stars were those which when data were collected, were found not to have 
been lately observed; when no good early authority was at hand. 

2. General basis. — The system of the Berlin Jahrbuch (Auwei's') was adopted. This is quite 
generally employed as a standard by many of the best modern observers. It is fortunately very 
near that of the American Ephemeris (Boss's), but is rather farther north on the average, a few 
hundredths of a second only for 1802. The Jahrbuch system agrees still more closely with the 
Pulkova Catalogue for 1885, which has reached me since the computations were closed. This 
catalogue is based on an entirely independent investigation, with newly graduated circle and new 

' constants of refraction. 

3. Precession. — Struve's were used, as in the princii^al ephemerides. The terms depending 
on the cube of the time were taken into account where necessary. 

4. Data employed in compilation. — All respectable catalogues of 1855 or since, with partial 
omission of the Eadcliff for 1860. In doubtful cases, the single years of the Radcliflf 1862-1875 
and of the Washington observations were consulted; and in all, the latest Greenwich volumes 
available and the Karlsruhe observations. 

Special search was made for prime vertical declinations at Pulkova, Kasan, Gotha, and 
Washington; and in the other short but very accurate catalogue lately published in the Astrono- 
mische Nachrichten. 

5. Proper motions. — Stars contained in Auwers' Bradley w( re examined if less than three 
observations in declination are there given. If indications were found that Bradley's observa- 



UNITED STATES AND MEXICAN BOUNDARY. 37 

tions were inaccurate, they were investigated from all available authorities old aud uew; but 
if Auwers' proper motion seemed to be correct, it was employed, as also iji case of three or more 
observations. 

Stars not in Bradley were also completely investigated; in this case Piazzi or Groombridge 
was most commonly the best old authority. The method of least squares was employed in nearly 
all cases, the few exceptions being those where there were but two groups of nearly contempo- 
raneous good observations. The system on which the proper motions were calculated was inter- 
mediate between Auwers and Boss, to agree with those of the Jahrbuch stars which are not in 
Bradley. The weights were usually assigned on the system employed by Auwers in publications 
14 and 17 of the Astronomische Gesellschaft; giving, however, one observation half weight, and 
unity 2-4. These values were also diminished for the less reliable series. Bradley's own data were 
taken with weight two-tenths for a single observation, three-tenths for two ; for more, as beforesaid, 
Auwers' proper motions were used without least squares reduction. The tiual i>robable errors 
were estimated on an average scale, where weight = 1 receives probable error ± 0.5". This is too 
large for the best modern observations. Piazzi and Groombridge were allowed weights = J, no 
matter how many observations are given in their catalogues. On the whole I think the final 
probable errors assigned are not too small, perhaps rather too large. 

6. Final declinations. — The final declinations are brought up by the help of the assigned 
proper motions and reduced to the Jahrbuch's system by Auwers' systematic corrections or others 
derived from Boss or other sources and reduced to Auwers'. The Jahrbuch stars were most com- 
monly reduced with the proper motions there given; but more recent observations were added 
to the material tliere employed. They were found in the Ten Year Catalogue and in the Pulkova 
Catalogue of Romberg, besides frequently in others, in addition to the original njaterial. 

INTRODUCTION TO THE REVISION. 

The systematic corrections on the Jahrbuch system by Professor Auwers within a short time 
were applied on the original calculation sheets, for the stars marked A and C in the revision 
sheets. Stars marked C will require an additional correction of -f 0.1" to the declinations on the 
average owing to the different system by which the proper motions were calculated. Stars marked 
B have been investigated anew by least squares from all available material using the new system- 
atic corrections throughout. New catalogues luive been added in all these cases where such were 
published after the computations for the main catalogue; especially valuable were Greenwich 
1800, year results, the new Glasgow Catalogue (1890), the prime vertical observations at Kasan, 
and the Cincinnati results reduced to 1900 for the proper motion stars. The following catalogues 
of fundamental stars received after the revision was nearly completed were not included: The 
Pulkova system of 1885 and the Madison of 1890. Both these agree closely in general with^he 
Jahrbuch system, aud the stars are so abundantly observed in detail elsewhere that the increase 
in accuracy would not be very considerable. Of course, if the latitudes on the boundary were to 
be redetermined the case would be difterent. 

According to my calculation (not duplicated for want of time) the sum of the corrections J 6 
to the catalogue positions is +3.54"; if we add to this 0.1" for each of the 68 stars C, where 
proper motions have not been recomputed, we shall have +10.is4" or +0.016" for the average of 
the 624 stars. This is the mean reduction of the latitudes to the system of the Astronomische 
Gesellschaft, which, on the other hand, is now a few hundredths of a second north of the American 
Ephemeris system (Boss). The separate values z? S for stars of Classes A and C are of no special 
importance except in the few cases where they are more than 0.1", owing usually to new material; 
but those for Class B, being derived from a complete new solution by least squares of equations 
derived from all available material, should be employed in any further use of this catalogue. 
The chief cause of variation is the change in the systematic corrections for older observations, 
especially Piazzi's; some rather doubtful cases have had uew material. 

The Jahrbuch star 33 Bootis was i-ecognized as discrepant by Mr. Porro, of Turin, in the 
Astronomische Nachrichten, too late for any change, even in the revision. But I looked over the 
material collected by Argelander, and on the basis of this Mr. Porro prepared a later article in 
which he adopted my liyi)othesis that the discrepancy was due to proper motion, as in almost all 
similar cases. This again was put as doubtful by Argelander himself. Bradley has only two 
observations, one of which was made below pole, at a very low altitude, and hence can not be 
used as confirmation of the other, which is perhaps 3" wrong. 



38 



UNITED STATES AND MEXICAN BOUNDARY. 



Mean declinations of latitude stars. 



Class. 


Ko. 


B. A. C. 


Mag. 


AR. 1892. 


Anoual 
Tariation. 


DecHnatior, 
1892. 


Probable 
error, 
1892. 


Pr< 
mo 


per 


Annual 
preces- Sec 


var. 


AS 










h. m. «. 


». 


. 










' 




c 


1 




6.1 


3 18 


+ 3.08 


24 51 35. 26 


*0.49 


0. 


000 


+20. 051 — 


015 


+0.14 


A 


2 


16 


5.2 


4 42 


3 


10 


45 28 15. 75 


.16 


_. 


0.6 


20.049 


018 




A 


3 


32 


5.0 


9 1 


3 


10 


19 36 21. 60 


.18 


+ • 


007 


20. 037 


026 


+ .10 


C 
A 


5 




6.1 

4.7 


9 34 
11 27 


3 
3 


10 
11 


26 41 0. 03 
38 4 55. 38 


.28 
.18 


-• 


030 
007 


20. 035 
20.028 


027 
031 


^Z 


52" 


C 


6 


57 


6.8 


12' 15 


3 


08 


1 5 17.67 


.16 


+ 


015 


20.024 


033 


— .07 


A 


7 


58 


4.5 


12 41 




12 


36 11 11.01 


.21 


— . 


047 


20. 022 


034 


— .01 


A 


8 


60 


6.1 


13 




14 


43 1129.25 


.23 


+ 


016 


20.020 


035 


+ .05 


C 


9 


68 


6.5 


15 42 




29 


67 13 24. 32 


.26 


— 


055 


20.006 


041 


- .02 


A 


10 


80 


5.9 


18 50 




27 


6113 57.04 


.17 


— 


006 


19.985 


048 


+ .06 


A 


11 


87 


6.0 


19 ,52 




07 


1 20 29.62 


.16 


_ 


Oil 


19. 977 


047 


— .02 


C 


12 


92 


6.5 


20 45 




25 


56 2 35.30 


.38 


+ • 


010 


19. 971 


051 




A 


13 


109 


5.6 


24 25 




15 


29 9 21.93 


.20 


_ 


057 


19, 939 


058 


— .03 


A 


14 


112 


6.1 


24 32 




06 


—4 33 15. 16 


.13 


_ 


009 


19.938 


056 


+ .06 


A 


IS 


prll6 


7.0 


25 10 




08 


15 26 27. 46 


.24 


+ 


022 


19.932 


058 


+ .u 


A 


16 


129 


5.8 


26 49 




09 


6 2132.29 


.21 


+ 


022 


19, 916 


061 


+ .01 


C 


17 


142 


6.2 


29 19 




08 


12 46 37.94 


.28 


_ 


054 


19. 889 


066 


+ ,06 


C 


18 


152 


5.6 


30 54 




24 


43 53 33.61 


.30 


+ 


020 


19.871 


072 


— .01 


A 


19 


155 


4.2 


31 7 




19 


33 7 28. 98 


.16 




000 


19. 868 


072 


+ .02 


A 


20 


163 


6.8 


32 33 




06 


-1 5 51.44 


.14 


_ 


025 


19.851 


072 


+ .04 


A 


21 


169 


Var. 


34 23 




36 


55 56 41. 65 


.16 


_ 


038 


19.828 


082 


+ .05 


A 


22 


173 


5.3 


35 16 




24 


38 51 57.29 


.24 


+ 


Oil 


19.816 


081 


— .19 


A 


23 


180 


5.1 


36 2 




32 


49 55 12. 56 


.18 


— 


003 


19.805 


084 


+ .04 


C 


24 


182 


6.4 


36 18 




41 


58 9 40.39 


.24 


_ 


007 


19.8f.2 


0S7 


— .02 


A 


25 


189 


5.0 


37 30 




30 


46 26 1.33 


.20 


_ 


024 


19.765 


087 


— .03 


C 


26 


197 


5.7 


38 26 




31 


47 16 20. 30 


.50 


-). 


033 


19.771 


089 




A 


27 


198 


4.8 


38 42 




32 


47 41 35. 26 


.16 


— 


016 


19.767 


090 


+ .04 


A 


28 


211 


5.5 


40 54 




17 


14 53 10.23 


.29 


_ 


050 


19.734 


090 


+ .07 


A 


29 


214 


6.0 


41 31 




16 


18 59 17. 88 


.23 


+ 


010 


19.726 


091 


+ .02 


A 


30 


215 


4.2 


41 37 




16 


23 40 46.57 


.16 


_ 


072 


19.723 


092 


+ .03 


A 


31 


219 


5.0 


42 43 




37 


50 22 44. 63 


.19 


— 


015 


19.714 


lUO 


— .02 


C 


32 


221 


5.9 


42 43 




09 


4 43 30.39 


.18 


— 


.15 


19.705 


092 


+ .01 


A 


33 


222 


4.6 


43 5 




11 


6 59 49. 72 


.14 


— 


037 


19,700 


093 


+ .08 


A 


34 


223 


5.5 


43 18 




17 


16 21 26.68 


.23 


_ 


197 


19.696 


095 


+ .02 


A 


35 


228 


5.7 


44 10 




58 


63 39 33. 78 


.17 


— 


018 


19. 681 


109 


-1- .02 


C 


36 


237 


6.4 


45 45 




08 


2 47 56.26 


.21 


_ 


070 


19.665 


098 


+ .04 


A 


37 


SU 


5.3 


48 35 




53 


58 23 15. 79 


.23 


— 


080 


19. 604 


117 


+ .01 


A 


38 


247 


5.9 


48 52 




16 


18 36 9.33 


.19 


_ 


070 


19.599 


106 


+ .07 


U 


39 


253 


2.1 


.W 11 




57 


60 7 .54. 18 


.14 


_ 


015 


19.574 


122 


+ .02 


A 


40 


254 


6.2 


50 14 




55 


58 35 50. 14 


.22 


_ 


070 


19. 573 


121 


+ .06 


C 


41 fr 


11 


5.9 


53 57 




37 


44 7 52.68 


.32 


_ 


025 


19.500 


123 


+ .02 


A 


42 


285 


5.3 


56 54 




27 


31 13 27. 30 


.17 


— 


020 


19.438 


126 




A 


43 


288 


4.2 


57 23 




11 


7 18 50. 43 


.17 




039 


19.427 


121 


- .03 


A 


44 




ec5.3 


50 53 




30 


20 53 40. 98 


.22 




015 


19.372 ! 


129 


+ • 12 


A 


45 


311 


6.4 


1 14 




10 


4 19 58. 96 


.19 


- 


119 


19.368 : 


126 


+ .04 


A 


46 


3 1 


6.3 


2 3 




30 


31 26 8. 38 


.23 


_ 


033 


10.322 


137 


+ .02 


A 


47 


327 


5.7 


3 25 




98 


68 12 13.15 


.20 


— 


023 


19.292 ! 


167 


- .02 


C 
C 


48 
49 




6.8 
5.9 


3 38 

4 11 




94 
40 


67 12 13. 57 
41 30 25.47 


.30 
.21 


I 


030 
040 


19.287 , 
19.272 


166 
145 


+ :o3 


337 


A 


50 


338 


5.7 


4 39 




84 


64 26 39. 34 


.18 


_ 


019 


19.260 


165 


+ .06 


C 


51 


345 


5.2 


1 5 9 




29 


30 51 0. 70 


.37 




000 


19.248 


143 




A 


52 


374 


5.9 


18 




06 


—1 33 0. 47 


.18 


l. 


220 


19. 143 


141 


1 .32* 


A 


62' 


384 


5.8 


11 7 




05 


- 3 4 8 44 


.18 


_ 


060 


19. 095 


144 


+ .01 


A 


53 


388 


5.2 


12 14 




09 


3 2 43. 98 


.18 


_ 


019 


19.065 


148 


.,, 


A 


54 


394 


6.4 


13 53 




94 


64 5 29. 10 


.33 


_ 


045 


19.029 


190 




A 


55 


401 


5.2 


15 9 




30 


28 10 24. 53 


.25 


_ 


088 


18.984 


163 


— .03 


A 


66 


404 


5.0 


15 59 




50 


44 57 45.37 


.20 


_ 


005 


18.961 


175 


-i- .03 


A 


57 


406 


6.9 


17 3 




06 


-1 52. 62 


.20 


+ 


002 


18.930 


150 


1- .02 


A 


58 


409 


5.8 


17 30 




41 


37 9 3.91 


.27 


+ 


001 


18.917 


170 


— 03 





m 




6,1 
3.0 


17 35 

18 45 




23 

87 


19 54 16. 40 
59 40 25.94 




- 


004 
036 


18.915 
18.880 


165 
197 




416 


C 


61 


425 


6.0 


1 19 58 




49 


42 53 49, 84 


.31 


- 


070 


18.845 


182 


+ .06 



* Glasgow position erroneous and now corrected. 



UNITED STATES AND MEXICAN BOUNDARY. 
Mean dedinalions of latitude stars — Contiuued, 



39 



cues. 


So. 


B.A.C. 


«,. 


AE. 1892. 


Annnal 
variation. 


Declination, P^^/jW' 
1892. 0^«l' 


=K. 


Annual 
pre«8. Sec 




__!' i 










h.m.s. 


». 


, „ 












, 


A 


62 


427 


5.1 


20 26 


+3.22 


18 36 36.48 ±0 


21 


+O.029 


H-18.830 — 


170 


+0 


12 


A 


63 


431 


5.8 


20 52 


3.23 


18 40 50.88 


23 


_ 


038 


18.818 


171 


_l_ 


02 


A 


64 


432 


5.0 


21 12 


3.66 


44 60 55. 86 


17 


_ 


104 


18.808 


187 


_ 


26 


A 


65 


442 


6.6 


23 25 


3.63 


6 44 10. 64 


26 


— 


057 


18.739 


170 


+ 


18 


A 


66 


441 


5.7 


23 37 


3.57 


46 26 59.78 


25 


_ 


042 


18. 733 


194 


^ 


02 


C 


6- 


446 


6.0 


24 3 


3.23 


17 47 49.93 


37 


— 


000 


18.719 


177 


_ 


03 


A 


68 


448 


5.0 


24 32 


3.13 


5 35 13.22 


18 


_ 


031 


18.704 


172 


_ 


02 


A 


69 


453 


3.8 


25 42 


3.20 


14 47 19. 83 


16 


— 


003 


18.667 


179 


+ 


07 


C 


70 


455 


7.0 


26 14 


3.22 


16 23 47. 55 


30 


_ 


210 


18.650 


180 


+ 


05 


A 


71 


456 


5.4 


1 26 52 


3.88 


58 40 39. 21 


13 


_ 


025 


18.629 


218 


+ 


09 


C 


72 


464 


6.6 


27 38 


3.14 


7 39 16. 52 


22 


— 


030 


18.604 


179 


+ 


01 


C 

c 


73 

74 




5.9 
5.9 


28 17 
31 4 


3.02 


7 34 39. 13 
57 26 37.45 


26 
34 


I 


075 

005 


18. 583 
18. 490 


173 

227 


- 


07 
05 


482 


A 


75 


487 


3.7 


31 22 


3.65 


48 4 51.09 


14 


— 


111 


18.480 


215 


+ 


01 


A 


76 


492 


5.2 


32 52 


3.58 


43 50 11. 22 


26 


— 


003 


18.429 


214 


_ 


02 


C 


77 


501 


5.8 


34 11 


3.56 


42 45 2.70 


32 


_ 


060 


18. 383 


216 




00 


A 


78 


499 


5.5 


34 33 


4.55 


70 4 36. 34 


20 


+ 


004 


18.370 


274 


— 


04 


C 
A 


79 
80 




6.1 

4.7 


35 17 
35 49 


3.32 
3.12 


25 11 59.94 ' 
4 56 27. 26 


23 


+ 


040 
005 


18. 345 
18.326 


204 
193 


- 


04 

05 


518 


A 


81 


623 


5.4 


36 38 


3.25 


19 44 35.88 


20 


_ 


668 


18. 297 


203 


-1- 


02 


C 


82 


525 


6.4 


1 37 10 


3.74 


56 69 35.20 


26 


— 


050 


18.277 


243 


— 


03 


A 


83 


537 


4.4 


1 39 41 


3.16 


8 36 50.29 


14 


— 


068 


18.185 


202 


_ 


03 


C 


84 


544 


6.1 


42 16 


3.51 


37 24 53. 67 


19 


— 


026 


18.089 


229 


+ 


03 


C 


'85 


562 


6.4 


45 56 


3.81 


60 56 27.46 


40 


_ 


000 


17. 948 


256 


+ 


04 


A 


86 


564 


3.4 


46 38 


4.26 


63 8 16. 52 


14 


— 


022 


17.921 


286 


— 


02 


A 


87 


569 


3.7 


46 55 


3.41 


29 3 8.89 


17 


_ 


231 


17.910 


231 


_ 


07 


A 


88 


574 


4.4 


47 58 


3.10 


2 39 14. 88 


15 


+ 


020 


17.869 


213 


+ 


03 


C 


89 


579 


5.8 


49 31 


3.63 


36 44 62. 58 


20 


+ 


006 


17. 807 


244 


+ 


01 


A 


90 


580 


5.8 


49 44 


3.53 


36 43 18. 22 


22 


+ 


019 


17.798 


245 


_ 


04 


C 


91 


609 


6.0 


1 53 39 


3.20 


11 46 14. 23 


22 


— 


040 


17. 637 


230 


— 


03 


A 


92 


611 


5.9 


65 1 


4.37 


63 62 5. 18 


17 


+ 


006 


17.580 


315 


+ 


02 


A 


93 


614 


5.1 


55 7 


3.96 


63 57 54. 46 j 


19 


+ 


008 


17.576 


285 


+ 


07 


C 


94 


624 


5.5 


56 39 


3.49 


32 45 47.95 


18 


_ 


010 


17.511 


256 


_ 


05 


A 


95 


630 


5.9 


67 32 


3.38 


25 24 63. 34 


24 


+ 


013 


17.473 


250 


+ 


06 


A 


96 


633 


.•i.8 


-u 39 


3.07 


—0 23 32. 56 


26 


+ 


032 


17. 468 


227 


+ 


15 


A 


97 


639 


6.4 


58 16 


3.06 


—0 51 30. 62 


16 


_ 


058 


17.441 


228 


4. 


02 


A 


98 


619 


5.0 


2 1 68 


3.59 


37 20 47. 48 


26 


— 


037 


17.279 


273 


+ 


02 


A 


99 


656 


:i.l 


3 7 


3.55 


34 28 34.36 


15 


_ 


033 


17.228 


272 


_ 


06 


A 


100 


661 


5.8 


4 20 


3.62 


38 3146.26 


23 


_ 


004 


17. 174 


280 


— 


06 


A 


101 


665 


5.8 


2 4 38 


3.30 


18 59 26. 08 


19 


_ 


031 


17. 160 


267 


-1- 


02 


A 


102 


666 


6.8 


5 3 


3.40 


25 25 38. 34 


26 


+ 


001 


17. 141 


265 


+ 


16 


A 


103 


66- 


6.4 


5 6 


3.49 


31 1 1.17 


29 


_ 


020 


17. 139 


272 


+ 


01 


A 


104 


668 


6.1 


6 1 


4.61 


66 1 4.03 


15 


_ 


004 


17. 097 


353 


_ 


02 


A 


105 


675 


5.3 


6 6 


3.46 


29 47 47.92 


18 


_ 


055 


17.093 


272 


_ 


02 


A 


106 


676 


5.2 


6 27 


3.74 


43 43 28.03 


26 


_ 


019 


17.077 


293 


+ 


07 


A 


107 


684 


4.5 


7 17 


3.18 


8 20 23.61 


16 


_ 


001 


17.039 


252 


+ 


05 


A 


108 


691 


5.3 


9 33 


3.53 


32 51 24. 10 


20 


_ 


021 


16.933 


283 




00 


A 


109 


693 


5.8 


9 35 


3.40 


24 32 31.67 


35 


_ 


085 


16. 932 


273 


+ 


03 


C 


110 




6.6 


10 28 


4.54 


63 55 26. 23 


28 


— 


040 


16. 891 


365 


— 


03 


A 


111 


696 


6.5 


2 10 29 


4.18 


57 54.32 


29 


_ 


010 


16. 890 


336 




00 


A 


112 


698 


4.3 


10 54 


3.55 


33 20 60.74 


17 


_ 


034 


16. 870 


287 


_ 


04 


c 


113 


702 


7.0 


11 55 


4.66 


63 50 17. 65 


36 




000 


16.822 1 


369 


+ 


05 


A 


114 


707 


5.6 


12 7 


3.32 


19 24 4.58 


16 


+ 


010 


16. 812 


272 


+ 


02 


A 


115 


710 


S.5 


12 41 


3.46 


28 8 38. 02 


23 


+ 


014 


16. 785 


284 


— 


02 


A 


116 


721 


5.4 


14 60 


4.14 


55 21 3.50 


20 


_ 


on 


16.682 


343 


_ 


09 


A 


117 


732 


5.8 


16 42 


3.07 


—1 22 37. 43 


21 


— 


052 


16. 590 


256 


+ 


03 


A 


118 


745 


5.5 


19 2 


3.21 


10 7 16. 37 


17 


_ 


013 


16.475 


274 


— 


03 


A 


119 


744 


4.3 


20 10 


4.85 


66 54 59. 05 


15 


+ 


003 


16.418 


415 


_ 


05 


A 


120 


757 


5.4 


21 50 


3.50 


29 11 12. 85 


18 


_ 


085 


16. 334 


304 


_ 


05 


A 


121 


759 


6.5 


2 22 28 


3.51 


29 26 44.01 


27 


+ 


066 


16. 301 


305 


+ 


02 


A 


122 


760 


4.3 


22 25 


3.18 


7 58 32.51 


13 


_ 


001 


16.304 


277 


— 


01 


A 


123 


772 


5.6 


25 31 


3.64 


35 40 4. 20 


22 


+ 


014 


16. 145 


322 




00 



40 



UNITED STATES AND MEXICAN BOUNDABY. 

Mean dccUiiallons of latitude Ktars— Continued. 



Class 


No. 


B. A. C. 


Mag. 


AR. 1892. 


Annual 
variation 


1 Declination, 
1892. 


Probable 
error, 
1892. 


Proper 
motion. 


preces 
sion. 


see. var. 


A5 










Ii.m.s. 


I ... 


, „ 




„ 


„ 


„ 




„ 


A 


124 


786 


5.6 


29 13 


+3.62 


34 12 57. 88 


±0.20 


—0.036 


+15.950 


-0 327 


—0 


08 


A 


125 


791 


5.8 


29 23 


3.95 


— 8 19 53.95 


.28 


— .071 


15.942 


.268 


_ 


16 


A 


126 


792 


6.7 


29 55 


3,01 


— 4 1 13.55 


.23 


— .427 


15.913 


.274 


_ 


16 


C 


127 


795 


7.0 


31 54 


5.46 


71 9 38. 69 


.21 


.000 


15. 808 


.499 


+ 


01 


A 


128 


808 


5.6 


32 41 


3.39 


21 29 38. 86 


.16 


— .011 


15.765 


.313 




01 


A 


129 


816 


5.9 


35 19 


4.25 


64 38 40.68 


.27 


— .025 


15. 621 


.395 


+ 


22 





130 


819 


6.1 


35 23 


4.19 


53 3 64. 50 


.35 


— .015 


16.618 


.390 




00 


A 


131 


830 


6.3 


2 36 40 


3.22 


10 16 61. 05 


.24 


— .028 


15.647 


.304 


+ 


05 


A 


132 


829 


5.7 


37 3 


3.89 


43 60 14. 63 


.24 


— .034 


16. 526 


.365 




03 


A 


133 


831 


4.9 


37 7 


3.60 


27 14 50. 03 


.17 


— .009 


16.622 


.331 


_ 


02 


A 


134 


844 


5.1 


39 4 


3.26 


11 69 27.51 


.20 


— .069 


15.413 


.310 


_ 


01 


A 


135 


845 


4.2 


39 6 


3.23 


9 39 28. 32 


.15 


-.020 


16.412 


.307 


_ 


02 


A 


130 


861 


4.9 


41 29 


3.56 


28 47 63.48 


.23 


— .110 


16, 278 


.342 


, . 


02 


A 


137 


866 


5.8 


42 29 


3.47 


24 44 13.58 


.28 


+ .002 


15.221 


.336 


+ 


02 


A 


138 


863 


3.8 


42 49 


4.67 


55 26 48. 08 


.19 


— .034 


15. 201 


.419 




05 


A 


139 


871 


4.6 


43 46 


3.75 


37 52 25. 40 


.21 


— .087 


16. 147 


.366 


_ 


10 


A 


140 


885 


4.1 


46 36 


4.21 


52 19 11. 96 


.13 


— .009 


14.984 


.416 


+ 


06 


A 


141 




7.0 


2 40 51 


4.10 


50 43 30. 36 


.37 


— .030 


14.969 


.410 


+ 


04 

05 


A 


142 


888 


5.8 


46 54 


3.77 


37 53 49.75 


.30 


— .063 


14. 967 


.372 


C 


143 


893 


6.5 


47 11 


3.33 


16 2 31.66 


.34 


— .075 


14. 950 


.330 


_ 


06 


C 


144 




6.3 


49 16 


3.94 


50 49 27. 10 


.32 


— .030 


14. 827 


.416 


+ 
+ 




C 


145 


914 


5.7 


62 30 


4.05 


46 47 15 68 


.29 


+ .020 


14. 636 


.410 


02 


C 


146 


943 


5.0 


57 26 


4.46 


56 16 51.85 


.26 


+ .065 


14.338 


.442 




06 


A 


'147 


'957 


5.7 


59 6 


3.51 


24 50 4. 10 


.23 


— .013 


14.235 


.366 




00 


A 


148 


963 


var. 


3 1 8 


3.88 


40 32 20.99 


.16 


+ .010 


14.109 


.409 




01 


A 


149 


967 


4.3 


2 13 


4.02 


44 26 51. 60 


.21 


— .160 


14.042 


.423 


+ 




A 


150 


974 


5.8 


3 7 


3.59 


28 39 60.46 


.21 


-.026 


13.986 


.382 




06 


A 


151 


981 


5.0 


3 4 19 


3.85 


39 12 3.34 


.21 


+ .020 


13.910 


.411 




07 


C 


162 


987 


6.3 


5 26 


.3.29 


12 38 16. 49 


.24 


+ .010 


13.840 


.363 




01 


A 


153 


986 


4.3 


5 27 


3.42 


19 19 4. 27 


.13 


+ .DOS 


13.838 


.366 




03 


C 


154 


991 


6.0 


6 42 


3.18 


6 16 13. 29 


.36 


- .010 


13.759 


.343 




01 


A 


155 


999 


4.8 


8 42 


3.44 


20 38 37. 94 


.18 


— .070 


13. 632 


.374 




10 


A 


156 


1,006 


6.6 


10 31 


4.01 


43 37 39. 13 


.23 


-.044 


13.514 


.438 




03 


A 


157 


1.007 


5.4 


10 56 


4.24 


49 49 33. 61 


.17 


— .027 


13.487 


.464 




01 


li 


158 


1,017 


5.0 


11 58 


3.74 


33 49 37. 98 


.21 


-.002 


13.420 


.411 


_ 


38 


A 


159 


1, 023 


5.9 


13 29 


3.67 


26 40 48.27 


.27 


— .080 


13.322 


..396 




01 


A 


160 


1, 028 


5.0 


13 42 


3.12 


2 58 25.50 


.17 


+ .110 


13.307 


.347 




00 


A 


161 


1,041 


6.0 


3 15 28 


3.13 


3 17 10. 23 


.23 


— .037 


13. 191 


.350 


_ 


03 


A 


162 


1.0.58 


4.5 


20 19 


4.82 


59 33 48.15 


.14 


1 .012 


12.808 


.544 


— 


05 


A 


163 


I, 099 


4.8 


28 49 


4.24 


47 49 57.92 


.20 


- .038 


12. 290 


.494 


+ 


08 


C 


164 


1,105 


6.6 


30 42 


4.04 


42 13 35. 50 


.30 


— . 020 


12. 159 


.473 




00 


A 


165 


i,ir2 


4.4 


31 22 


3.07 


3 30. 23 


.20 


— .501 


12. 113 


. 362 


+ 


07 


C 


166 


1,114 


6.5 


31 44 


3.37 


15 4 31. 54 


.32 


- .010 


12.087 


.396 


-1- 


06 


A 


167 


1,111 


5.5 


32 47 


5.15 


62 51 58. 20 


.18 


H .058 


12.013 


.608 




00 


C 


168 


1,123 


5.S 


34 6 


3.90 


37 13 51.21 


.27 


- .040 


11.921 


.461 


— 


01 


A 


169 


1,128 


5.9 


34 14 


3.12 


2 43 19.01 


.22 


+ .019 


11.912 


.372 


— 


04 


A 


170 


1,132 


5.0 


35 32 


3.86 


33 37 5. 00 


.26 


-.003 


11. 820 


.452 


— 


01 


A 


171 


1,135 


5.5 


3 36 5 


3.45 


19 21 14. 18 


.18 


— .007 


11.781 


.412 


+ 


02 


B 


173 


1,133 


5.3 


36 36 


.5.19 


63 11 80 


.28 


— .010 


11.745 


.620 


+ 


40 


A 


173 


1,138 


4.0 


37 33 


3.75 


31 66 44. 21 


.22 


- .010 


11.677 


.449 


_ 


07 


A 


174 


1,139 


4.0 


37 51 


4.05 


42 14 12. 35 


.17 


-.012 


11.666 


.487 


+ 


01 


A 


175 


1,140 


6.2 


37 32 


3.55 


19 19 23. 48 


.21 


— .034 


11.677 


.414 


-1- 


02 


C 


176 


1,143 


6.9 


38 11 


3.48 


20 35 13. 82 


.27 


.000 


11.632 


.419 


_ 


02 


c 


177 


1,142 


5.9 


38 26 


■ 4.18 


45 20 31. 70 


.31 


— .020 


11.614 


.501 


+ 


10 


A 


178 


1,137 


4.5 


38 58 


6.22 


70 69 54. 94 


.20 


-.051 


11.576 


.748 


-(- 


04 


A 


179 


1, 1.58 


6.0 


39 25 


3.06 


— 38 12. 82 


.2! 


; .012 


U. 643 


.370 


+ 


22 


A 


180 


1,161 


4.9 


39 55 


3.55 


23 36 41.21 


.20 


— .042 


11.604 


.429 


+ 


03 


C 


181 




5.9 


3 41 41 


4.12 


43 37 44.. 38 


.40 


+ .010 


11. 381 


.500 


..|_ 


02 


c 


182 


1,192 


5.8 


43 49 


3.59 


25 15 10.72 


.28 


— .110 


11. 226 


.439 


- 


02 


c 


183 


1,206 


6.0 


46 59 


3.43 


17 17.90 


.19 


— .036 


10. 995 


.421 




00 


A 


184 


1,212 


5.6 


47 22 


2.96 


-5 41 3.16 


.18 


— .007 


10. 969 


.366 


- 


10 



' apart: mean of the t 



UNITED STATES AND MEXICAN BOUNDARY 
Mean declinations of latitude stars — Continued. 



41 



- 


No. 


B.A.C. 


Mag. 


AR. 1892. 
h. m. .. 


Annual 
variation. 


Declination, ^'^ 

1892. «7g 


ri»i 


Annual 
preeeu- Sec 


var. 


di 










». 


, „ 


! 




„ 


, 




A 


185 


1,214 


4.5 


48 35 


+4.43 


50 22 55.01 ±0 


17 -0 


125 


+10. 879 — 


547 


+ 0.09 


A 


186 


1,219 


3.3 


50 36 


4.01 


39.41 50.20 


15 1- 


016 


10. 730 


499 


— .10 


A 


187 


1,228 


4.1 


51 .57 


3.88 


35 28 47. 69 


16 ) — 


013 


10. 630 


484 


— .09 


A 


188p. 


1, 238' 


6.7 


54 32 


3.58 


22 53 48.05 


28 j- 


016 


10. 438 


447 


+ .05 


C 


189 


1,240 


5.9 


54 35 


3.44 


17 53 19. 52 


31 ! - 


047 


10.434 


433 


.00 


A 


■190 


1,241 


{';^f} 


54 42 


3.32 


12 11 4.89 


14 1 — 


009 


10.426 


418 


^■ .01 


A 


191 


1,262 


5.3 


59 59 


3.67 


27 18 29.44 


24 — 


061 


10.028 


468 


+ .06 


A 


192 


1,266 


4.3 


4 49 


4.33 


47 25 24. 72 


14 — 




9.964 


553 


+ .08 


A 


193 


1.268 


6.3 


1 7 


3.65 


37 26 37. 25 


27 — 


142 


9.942 


500 


+ .05 


A 


194 


1,279 


5.8 


4 15 


3.64 


26 11 54.98 


17 — 


037 


9.703 


470 


— .08 


A 


195 


1,287 


4.1 


6 58 


4.38 


48 8 3.33 


19 — 


027 


9.494 


507 


+ .07 


A 


196 


1,302 


0.2 


9 38 


3.40 


15 7 47. 90 


20 — 


010 


9.287 


442 


— .10 


C 


197 


1,301 


4.9 


10 7 


4.48 


50 1 45. 36 


22 j - 


050 


9.250 


685 


+ .04 


A 


198 


1,322 


5.4 


13 24 


3.89 


34 18 19.31 


20 + 


001 


8:995 


511 


.00 


A 


199 


1,323 


.^.0 


13 44 


4.32 


46 14 24.47 


22 - 


040 


8.968 


567 


+ .03 


A 


200 


1,328 


4.0 


13 39 


3.41 


15 21 58. 59 


16 — 


030 


8.975 


447 


+ .07 


A 


201 


1,346 


4.0 


4 16 42 


3.45 


17 17 19.48 


16 — 


025 


8.735 


456 


— .08 


A 


202 


1,350 


6.0 


17 13 


3.43 


16 31 28.47 


23 — 


032 


8.694 


454 


+ .03 


A 


203 


1,357 


5.3 


17 58 


3.26 


9 12 32.84 


26 — 


004 


8.635 


434 


— .04 


A 


204 


1,364 


5.7 


19 14 


3.81 


31 11 40. 55 


30 - 


116 


8.536 


506 


+ .03 


A 


205 


1,371 


5.9 


20 50 


3.58 


22 45 8.50 


20 — 


003 


8.409 


478 


.00 


C 


206 


1,373 


6.0 


21 36 


3.55 


21 22 -42. 44 


31 — 


050 


8.348 


474 


— .04 


A 


207 f 


11 1,382 


5.7 


23 29 


4.73 


53 40 31.30 


14 — 


009 


8.198 


633 


+ .10 


C 


209' 


11 1,398 


5.8 


25 49 


4.21 


42 49 57. 22 


21 


000 


8.011 


566 


+ .07 


A 




1,414 


4.8 


29 12 


4.14 


41 2 31. 84 


23 — 


024 


7.738 


561 


— .04 


A 


209 


1.421 


4.6 


29 43 


3.21 


9 56 18. 84 


25 — 


054 


7.696 


446 


+ .06 


A 


210 


1,424 


5.7 


3125 


4.73 


53 15 34.46 


17 — 


091 


7.560 


627 


— . 03 


A 


211 


1,425 


5.7 


4 31 24 


4.71 


52 61 48. 74 


20 - 


019 


7.560 


639 


— .04 


A 


212 


1,442 


5.6 


34 3 


3.33 


11 59 5. 27 


25 - 


022 


7.346 


455 


+ .11 


B 


213 


1,460 


5.7 


38 27 


3.31 


10 56 40. 37 


32 + 


007 


6.986 


456 


+ .13 


A 


214 


1,456 


5.6 


39 


4.58 


56 33 52. 25 


14 j- 


156 


6.940 


683 


+ .07 


A 


215 


1,469 


3.9 


40 6 


3.00 


- 3 27 11. 14 


14 : — 


002 


6.850 


413 


— .06 


A 


216 


1,474 


4,5 


43 19 


5.92 


66 9 30. 08 


12 — 


001 


6.585 


820 


+ .02 


A 


217 


1,491 




44 43 


3.26 


8 42 51.51 


21 — 


031 


6.468 


463 


- .01 


A 


218 


1,495 


4.1 


45 27 


3.19 


5 25 11.73 


16 - 


002 


6.408 


444 


— .03 


A 


219 


1,494 


5.8 


46 13 


4.89 


55 4 48.40 


22 — 


0U9 


6.345 


679 


+ .10 


A 


220 


1,514 


3.8 


48 38 


3.12 


2 15 48. 09 


13 - 


007 


6.145 


436 


+ .01 


A 


221 


1,528 


5.8 


4 5133 


3.67 


24 52 58.87 


20 — 


019 


5.901 


513 


-.02 


A 


222 


1,535 


6.4 


52 57 


4.12 


39 29 26.13 


27 — 


006 


5.784 


579 . 


- .13 


A 


223 


1,536 


4.3 


53 49 


5.31 


60 17 0.80 


14 — 


014 


5.711 


746 


— .10 


A 


224 


1,540 


var. 


54 13 


4.30 


43 39 46. 21 


15 — 


014 


5.677 


603 


+ .03 


A 


225 


1,541 


3.9 


54 56 


4.18 


40 55 3. 36 


15 — 


008 


.5. 617 


588 


— .07 


A 


226 


1.551 


4.8 


56 38 


3.58 


21 26 6. 42 


16 - 


040 


5.473 


504 


-.02 


A 


227 


1,558 


3.5 


58 56 


4,20 


41 5 16. 16 


14 — 


061 


5.279 


593 


-.06 


A 


228 


1,568 


5.2 


5 14 


3.54 


18 29 58.20 


19 + 


022 


5.100 


497 


+ .08 


B 


229 


1,572 


5.8 


1 32 


3.65 


24 7 18. 68 


30 


000 


5.061 


517 


+ .22 


C 


230 


1,582 


6.0 


2 40 


4.45 


46 49 40.17 


26 - 


160 


4.964 


631 


+ .03 


C 


231 


1,601 


5.7 


5 5 29 


3.44 


15 54 41. 96 


27 + 


010 


4.725 


490 


+ .04 


A 


232 


1,614 


5.3 


8 22 


3.90 


32 33 43.41 


22 + 


013 


4.479 


555 


+ .00 


A 


233 


1,027 


5.0 


11 5 


3.92 


33 15 29.46 


22 - 


154 


4.247 


662 


+ .05 


A 


234 


1,642 


5.4 


14 13 


5.12 


57 26 18.78 


20 — 


058 


3.979 


734 


+ .02 


A 


235 


1,663 


5.7 


17 19 


4.07 


37 17 2. 05 


21 + 


001 


3.713 


585 


+ .04 


A 


236 


1,687 


1.9 


19 21) 


3.22 


6 15 4.52 


16 — 


015 


3. 539 


463 


+ .08 


A 


237 


1.681 


2.0 


19 28 


3.79 


28 30 56. 24 


14 - 


180 


3.528 


545 


+ .01 


A 


238 


1.676 


5.9 


19 68 


5.65 


62 58 33. 81 


14 — 


008 


3.485 


816 


- .01 


A 


239 


1.730 


2.2 


26 29 


3.06 


— 22 46.83 


16 - 


005 


2.922 


443 


+ .03 


A 


240 


1.748 


4.9 


5 28 53 


3.29 


9 24 57. 10 


20 — 


002 


2.714 


477 


+ .09 


A 


241 


1,766 


4.6 


5 30 58 


3.29 


9 13 53.20 


23 - 


305 


2.533 


477 


+ .07 


B 


242 


1,751 


5.9 


31 37 


0.00 


65 38 10.87 


31 — 


036 


2.477 


870 


+ .03 


A 


243 


1.794 


1.9 


35 19 


3.02 


— 2 0.50 


16 + 


010 


2.156 


440 


+ .16 


A 


244 


1,797 


6.2 


37 24 


5.05 


56 4 12. 08 


20 — 


051 


1.974 


734 


.00 


A 


245 


1,837 


5.2 


42 23 


3.68 


24 31 50. 69 


20 - 


010 


1.539 


536 


+ .01 



S. Doc. 247- 



UNITED STATES AND MEXICAN BOUNDARY. 

Mean declinations of latihide stars — Continued. 



Class. 


No. 


B.A.C. 


Mag. 


AR. 1892. 


variation. 


Declination, ^^^ 
1892. YJ 


able 
2.' 


Proper 


Aunnal 

Preces- 


Sec. var. 


AS 




240 


1,845 


4.1 


h.m.e. 
44 


+4.15 


39 58.32 ±0 


16 


+0.032 


+ 1.398 


-0. 605 


-0 


02 


C 


247 


1,870 


4.8 


47 59 


3.55 


20 15 19. 66 


17 


— .096 


1.051 


.520 




00 




248 


1,885 


4.0 


50 38 


4.94 


64 16 32.23 


14 


- .117 


.819 


.719 


— 


03 


C 


249 


1,896 


6.3 


61 18 


3.72 


25 56 23. 31 


21 


— .005 


.762 


.543 


+ 


04 


A 


250 


1,895 


2.0 


51 36 


4.40 


44 56 8. 65 


16 


- .011 


.734 


.042 


+ 


03 


,. 


251 


1,928 


4.7 


50 26 


3.30 


9 38 48. 56 


31 


+ .020 


.311 


.481 


— 


00 


A 


252 


1,945 


6.9 


.19 10 


3.17 


4 9 51.03 


16 


- .013 


,064 


.462 


— 


03 


A 


253 


1,958 


4.6 


1 24 


3.42 


14 46 50.97 


14 


— .013 


- .123 


.499 


+ 


03 


A 


254 


1,963 


6.8 


3 20 


4.00 


48 43 55. 44 


24 


— .063 


.292 


.670 


H 


06 


A 


255 


1,992 


5.7 


7 67 


5.54 


61 32 57. 46 


21 


— .005 


,096 


.807 


— 


06 


A 


256 


2,009 


5.0 


9 11 


3.46 


16 10 32.72 


18 


+ .005 


,804 


.504 


+ 


08 


A 


257 


2.017 


5.5 


10 23 


3.37 


12 18 6.24 


18 


+ .199 


.908 


.490 


_ 


03 


A 


258 


2,022 


5.7 


11 9 


3.31 


9 58 52. 01 


23 


-.059 


.976 


.481 


— 


01 


A 


259 


2,024 


r,.7 


12 59 


4.87 


63 30 1.93 


23 


— .090 


1.136 


.709 


+ 


17 


A 


260 


2,044 


5.4 


16 36 


4.63 


49 20 32. 30 


16 


— .012 


1.450 


.072 




00 


C 


261 


2,040 


5.7 


6 17 19 


5.07 


56 20 29. 22 


50 


.000 


1.513 


.737 


+ 


18 


A 


262 


2, 074 


6.2 


21 24 


5.22 


58 14 28. 30 


17 


-.334 


1.870 


.757 


+ 


01 


A 


263 


2, 120 


4.8 


27 4 


3.25 


7 24 41.48 


21 


-r .004 


2.363 


.409 


+ 


12 


A 


264 


2,156 


5.7 


31 18 


4.18 


39 59 39.85 


22 


— .011 


2.730 


.603 


+ 


09 


A 


2641 


*2, 163 


2.2 


31 28 


3.47 


16 29 27. 34 


13 


— .036 


2.745 


.499 


+ 


04 


A 


265 
266 




6.1 
3.3 


31 X- 
37 17 


3.22 
3.69 


6 13 32. 69 
25 14 15. 09 


60 
14 


+ .037 
— .005 


2.757 
3.248 


.464 
.530 


- 


09 


2,194 


A 


267 


2, 192 


5.8 


37 37 


5.13 


67 16 49.63 


22 


— .037 


3.277 


.736 


+ 


07 


A 


268 


2,200 


5.6 


38 57 


4.33 


43 41 3. 06 


18 


+ .147 


3.392 


.641 




00 


A 


269 


2,201 


5.7 


39 26 


4.68 


48 54 10.21 


23 


-.004 


3.433 


.677 


+ 


03 


A 


270 


2,223 


5.1 


43 8 


4.25 


41 54 27. 52 


27 


— .130 


3.751 


.607 


+ 


08 


A 


271 


2,233 


5.6 


6 45 5 


3.00 


2163 16.70 


26 


— .038 


3.919 


.513 




00 


A 


272 


2,235 


6.4 


45 36 


4.13 


38 59 49. 99 


22 


+ .002 


3.963 


.589 


— 


03 


A 


273 p 


2,275 


6.8 


62 8 


3.70 


26 13 20.21 


21 


+ .083 


4,522 


.526 


+ 


03 


A 


274 


2,330 


5.7 


7 2 10 


3.44 


16 6 9.30 


19 


— .104 


5,374 


.482 


+ 


04 


A 


275 


2,350 


5.9 


6 53 


3.65 


24 18 31.45 


18 


-.037 


6.685 


.608 


_ 


03 


15 


270 


2,361 


;>.7 


7 49 


4.46 


47 25 52. 26 


37 


— .162 


6.847 


.020 






A 


277 


2, 381 


5.8 


10 32 


4.19 


41 4 28.16 


18 


+ .023 


6.074 


,579 


^ 


15 


A 


278 


2,410 


3.5 


13 40 


3.69 


22 10 50. 71 


17 


1- .003 


6,336 


.494 


-1- 


09 


A 


279 


2,416 


5.5 


14 50 


4.02 


30 57 47. 30 


16 


— .009 


6.431 


.,553 


„ 


06 


A 


280 


2,467 


5.3 


22 37 


3.75 


28 20 24, 44 


22 


— .053 


7.073 


.508 


— 


01 


A 


281 


2,469 


5.0 


7 23 6 


3.74 


28 8 17.99 


22 


-.018 


7.112 


.507 


+ 


01 


A 


282 


2,480 


5.6 


20 30 


3.12 


2 8 35.22 


27 


+ .023 


7.390 


.420 




05 


A 


283 


2,504 


5.9 


3! 27 


3.94 


35 17 23.28 


24 


+ .024 


7.791 


.526 


+ 


02 


A 


284 


2,533 


6.6 


36 41 


,5.48 


63 6 24. 38 


19 


— .066 


8,210 


.724 




00 


A 


285 


3,549 


5.9 


37 32 


3.67 


26 2 26.70 


21 


-.026 


8.278 


.483 


^ 


10 


li 


286 




5.7 


39 27 


4.02 


37 46 42. 00 


40 


+ .030 


8.431 


.527 


+ 


10 


A 


237 


2,606 


6.2 


46 38 


4.38 


47 39 53. 08 


25 


— .014 


8,997 


.567 


+ 


02 


A 


288 


2,639 


6.1 


60 52 


3.41 


16 4 41.97 


21 


— .026 


9, 326 


.436 


+ 


03 


]i 


289 




6.0 


55 31 


3.18 


5 10 35. 40 


50 


+ .037 


9. 685 


.401 




00 




290 


2,704 


6.0 




4.97 


58 33 49. 70 


33 


— .075 


10, 117 


.620 






B 






6.1 


18 10 


3.85 


35 21 36. 66 


50 


.000 


11.370 


.458 




04 


A 


292 


2,815 


6.0 


19 54 


3.06 


28 14 55. 57 


20 


— .117 


11.494 


.434? 


+ 




A 


293 


2,842 


6.4 


24 56 


i.d 


65 30 45.76 


17 


-.063 


11.8.52 


.636 


_ 


06 


C 


294 




6.1 


28 34 


3.04 


— 1 47 1. 15 


60 


.000 


12. 108 


.348 


+ 


35 


A 




2,892 


6.0 


31 17 


4.47 


53 5 22.49 


25 


-.031 


12.296 


,511 




09 


A 


296 


2,958 


5.8 


38 53 


3.26 


10 28 21.27 


31 


+ .007 


12.815 


.363 


_ 


07 


A 


297 


2,076 


6.4 


41 47 


3.06 


- 1 30 6.00 


26 


+ .017 


13.008 


.332 


_ 


34 


A 


WT 


3,003 


5.8 


47 22 


5.22 


65 59.26 


17 


— .090 


13. 376 


.560 


+ 


14 


A 


298 f 


U 3,052 


5.6 


51 33 


3.36 


15 59 44. 59 


22 


+ .030 


13.647 


.355 


+ 


01 


A 


299 


3,075 


3.5 


56 15 


4.13 


47 34 59.41 


17 


— .068 


13. 946 


.426 




01 


A 


300 f 


11 3,162 


4.0 


9 12 7 


3.75 


37 15 33. 50 


17 


— .114 


14. 909 


.359 




00 


A 


301 


3,204 


4.6 


18 22 


3.51 


26 38 49.13 


19 


-.036 


16. 269 


.326 


_ 


13 


B 


302 


3,273 


5.0 


30 18 


3.57 


31 38 44. 45 


36 


- .012 


15. 925 


.311 


_ 


95 


C 
A 






6.1 


35 12 
44 46 


3.66 
4.13 


3146 5.64 
54 34 7. 42 


50 
18 


.000 
+ .025 


16. 182 
16.661 


.301 
.327 




04 
02 


304 


3,358 


4.7 


- 



UNITED STATES AND MEXICAN BOUNDARY. 
Mean declinatioM of latitude stars — Contiuued. 



43 



Class. 


No. 


B.A.C. 


Mag. 


AE. 1892. 


Annual 
variation. 


Declination, P™^ 
1892. 7/ 


able 
2.' 


Proper 
motion. 


Annual [ 
preces- | Sec 


.a. 


A6 


A 


305 


3,407 


6.4 


h.m.i. 
52 24 


+3.18 


8 49 45.46 ±0 


25 


-0. 015 


—17. 024 -0 


238 


+0.04 


A 


300 


3,505 


3.5 


10 10 35 


3.04 


43 27 12. 02 


15 


_ 


058 


17. 811 


218 




02 


A 


307 


3,522 


5.7 


13 51 


3.27 


20 1 7.70 


20 


_ 


201 


17.941) 


207 


_ 


06 


A 


308 


3,531 


5.0 


16 20 


4.40 


66 6 44. 40 


16 


_ 


014 


18.036 


272 




00 


A 


309 


3,590 


5.1 


24 


3.05 


— 2 11 11.39 


18 


_ 


018 


18. 319 


173 


+ 


19 


A 


310 


3,593 


4.9 


25 54 


5.28 


76 16 8 71 


17 


_ 


005 


18.386 


298 




01 


B 


311 


3,637 


var 


10 32 13 


2.96 


-12 49 23.00 


36 




000 


18.600 


153 




00 


A 


312 


3,691 


5.8 


40 35 


3.24 


19 27 39. 02 


21 


_ 


036 


18. 861 


152 


+ 


08 


A 


313 


3,729 


4.9 


47 46 


3.47 


43 45 53. 11 


19 


_ 


027 


19.065 


148 


_ 


01 


A 


314 


3,749 


6.0 


50 9 


3.09 


1 18 45. 42 


20 


+ 


008 


19. 129 


126 


_ 


12 


A 


315 


3,777 


2.0 


57 4 


3.76 


62 20 2. 31 


15 


_ 


071 


19. 301 


141 


_ 


01 


A 


316 


3,784 


5.8 


58 31 


3.35 


38 49 22. 76 


21 


_ 


013 


19. 336 


121 


+ 


01 


A 


317 


3,788 


4.8 


59 27 


3.10 


7 55 11.43 


15 


_ 


022 


19. 357 


111 


_i. 


07 


A 


318 


3,801 


6.5 


11 153 


3.22 


23 54 26.44 


29 


.). 


016 


19.411 


111 


+ 


06 


B 


319 


3,825 


6.7 


6 27 


3.52 


55 28 52.15 


50 


_ 


002 


19. 508 


111 




05 


A 


320 


3,842 


5.0 


9 28 


3.20 


23 41 2. 64 


21 


+ 


003 


19.567 


094 


+ 


06 


A 


321 


3,856 


4.7 


11 13 15 


3.29 


38 46 40.19 


26 


_ 


068 


19.637 


089 


+ 


01 


A 


322 


3,862 


4.2 


15 34 


3.10 


6 37 16.10 


14 




000 


19. 677 


079 




00 


B 


323 


3,864 


5.9 


16 26 


3.61 


64 55 17. 35 


17 


+ 


040 


19. 692 


091 


_ 


05 


B 


324 




6.0 


23 41 


3.41 


57 20 1. 57 


36 


_ 


012 


19. 802 


070 




27 


A 


325 


3,916 


5.0 


24 48 


3.06 


— 2 24 27. 53 


13 




ODD 


19.817 


060 


+ 


13 


A 


326 


3,933 


5.5 


29 43 


3.58 


69 55 25.59 


17 


_ 


127 


19.878 


068 




01 


B 


327 


3,953 


6.1 


32 45 


3.25 


47 25 58. 37 


32 


_ 


034 


19.911 


048 


+ 


63 


B 


328 


3,975 


6.5 


38 24 


3.06 


-6 4 35.56 


27 


_ 


023 


19.964 


034 




30 


A 


329 


3, 981 


4.0 


40 21 


3.19 


48 22 41. 60 


15 


+ 


030 


19. 979 


032 




00 


A 


330 


3,995 


2.1 


43 33 


3.00 


15 10 32. 87 


14 


_ 


098 


20.001 


024 


j^ 


03 


A 


331 


4,017 


2.4 


11 48 9 


3.18 


54 17 42. 78 


15 


+ 


008 


20.026 


016 


+ 


02 


C 


332 




6.1 


51 41 


3.12 


40 56 48.21 ] 


34 


_ 


060 


20.040 


008 


_ 


11 


A 


333 


4,066 


5.9 


58 45 


3.08 


22 3 38.21 1 


22 


+ 


004 


20.053 + 


00 1 


_ 


01 


A 


334 


4,072 


4.2 


59 42 


3.06 


9 19 58. 17 


14 


+ 


049 


20.053 


008 


_). 


03 


A 


335 


4,110 


5.8 


12 6 40 


3.06 


21 8 36.41 


26 


_ 


018 


20.044 


020 


_ 


01 


A 


336 


4,126 


5.8 


10 43 


3.02 


41 15 40.83 


18 


_ 


031 


20.031 


029 


_ 


03 


A 


337 


4,151 


5.2 


14 52 


3.04 


3 54 50. 55 . 


19 


_ 


063 


20. Oil 


037 


_). 


(15 


A 


338 


4,195 


4.6 


21 33 


3.00 


28 52 7. 56 


17 


_ 


086 


19.964 


050 


_ 


06 


B 


339 




6.0 


22 15 


2.96 


41 57 10.73 


35 


_ 


012 


19.958 


050 




03 


A 


340 


4,212 


5.8 


24 18 


3.01 


21 29 39.39 


20 


_ 


017 


19.940 


056 


+ 


01 


A 


341 


4,216 


5.6 


12 24 55 


2.83 


59 0.23 


13 


+ 


100 


19. 934 


053 


_ 


03 


B 


342 


4,233 


5.3 


28 20 


2.96 


33 50 39.60 


30 


— 


025 


19.900 


062 


_ 


50 


A 


343 


4,246 


5.2 




2.57 


70 37 1.38 


23 


_ 


005 


19.879 


058 


+ 


02 


A 


344 


4,248 


6.0 


31 33 


3.01 


17 41 4.57 


21 


_ 


022 


19. 863 


069 


+ 


03 


A 


345 


4,257 


4.9 


33 40 


3.09 


- 7 24 4.44 


13 


_ 


021 


19. 837 


075 


+ 


14 


B 


346 


4,282 


6.2 


39 21 


2.85 


44 41 38. 17 


36 




000 


19. 758 


080 


+ 


03 


B 


347 


4,287 


5.6 


40 3 


2.83 


46 1 50.09 


26 


+ 


005 


19. 747 


080 


^ 


21 


A 


348 


4,315 


5.0 


46 26 


2.93 


28 7 42. 37 


17 


_ 


018 


19.643 


094 


_ 


07 


A 


349 p 


■ec4,318 


6.3 


46 50 


2.98 


17 39 41.57 


31 




000 


19. 636 


096 


_ 


07 


C 


350 




6.2 


49 4 


2.88 


34 7 10.23 


45 


+ 


015 


19. 595 


098 


_ 


03 


A 


351 


4,347 


'..1 


12 51 11 




66 1 27. 65 


24 




051 


19. 555 


087 


- 


05 


A 


352 


4,351 


5.1 


53 35 


2.97 


17 69 30.43._ 


23 


+ 


052 


19. .507 


109 


-1- 


17 


A 


353 


4,352 


5.9 


54 6 


3.09 


— 3 13 45. 43 "■ 


17 


+ 


010 


19.497 


114 


— 


y 


A 


354 


4,365 


5.7 


55 50 


2.31 


67 10 47.82 


18 


_ 


013 


19.461 


090 


_ 


B 


355 


4,389 


5.9 


13 1 1 


2.71 


45 50 45. 87 


32 


+ 


025 


19.346 


113 


+ 


13 


A 


356 


4,388 


6.0 


1 7 


2.95 


23 11 44.76 


26 


_ 


031 


19.344 


121 


+ 


14 


A 


357 


4,401 


4.4 


4 21 


3.10 


— 4 67 44. 57 


14 


- 


037 


19. 267 


134 


+ 


07 


A 


358 p 


ec 4, 408 


6.3 


4 44 


2.77 


39 6 33. 51 


27 


+ 


007 


19. 258 


122 


— 


01 


B 


359 


4,423 


6.0 


7 10 


2.99 


12 7 50. 14 


28 


_ 


024 


19. 198 


134 


_ 


14 


B 


360 




6.6 


9 47 


2.09 


67 51 36. 45 


34 


+ 


004 


19. 131 


099 


_ 


25 


A 


361 


4,456 


5.0 


13 13 39 


2,56 


50 15 0,06 


22 




001 


19. 026 


127 


_ 


06 


A 


362 


4,477 


6.1 


17 43 


3.10 


—4 21 33.45 


24 


— 


010 


18.911 


159 


+ 


45 


B 


363 


4,497 


6.6 


22 18 


2.06 


63 48 56. 75 


17 


+ 


207 


18. 773 


117 


— 


36 


A 


364 


4,506 


5.9 


23 23 


1.52 


72 57 8. 33 


26 


_ 


023 


18.740 


088 


+ 


07 


C 


365 


4,502 


6.5 


23 42 


3.08 


-0 48 13. 28 


32 


— 


060 


18.730 


167 


— 


02 


A 


366 


4,521 


5.4 


27 17 


3.15 


-9 36 30. 37 


22 


- 


023 


18.616 


179 


+ 


17 



44 



UNITED STATES AND MEXICAN BOUNDARY. 
Mean declinations of latitude stars — Continued. 



Class. 


~Ko. 


B. A. C. Mag. 


AK. 1892. 


Annual 
variation. 


Declination, '^^°^^ 
1892. jg 


able 
2'. 


Proppi- 
motion. 


Annual 
preces- 
sion. 


Sec.v.^r. 


A« 










h. m. s. 


s. 


, „ 




,. 








B 


367 


4.526 1 6 




27 41 


-1-2.84 


M 54 27.80 ±0 


31 


—0.200 


—18. 603 


+0. 163 


-0.10 


C 


:i68 


4,536 1 5 




29 58 


2.68 


37 44 8.58 


17 


-.015 


18. 527 


.1.58 


+ .02 


A 
A 


369 

370 






34 35 

35 31 


1.43 
2.80 


71 47 30.90 
20 30 7.47 


19 
19 


+ .011 
+ .023 


18. 369 
18.336 


.092 
.177 


.00 
+ .03 


4.562 1 5 


A 


371 


4,505 1 5 




13 35 57 


3.14 


— 8 9 28.52 


14 


+ .046 


18.321 


.195 


+ .02 


J! 


372 
373 






37 53 
41 .38 


2.57 
2. 56 


42 13 0.95 
41 37 49. 18 


27 
34 


H- .015 
— .058 


18. 252 
18. 113 


.163 
.168 


— .15 

+ .22 


4,596 1 6 


A 


37i 


4, 607 I 




43 17 


2.37 


49 51 8.64 


13 


— .014 


18.051 


.160 


+ .06 


A 


375 


4,618 ' 5 




44 36 


2.83 


21 48 1.15 


23 


+ .016 


18.000 


.190 


+ .05 


li 


376 






47 1 


2.94 


12 41 .56. 58 


41 


- .020 


17.906 


.201 


— .28 




377 


4,649 5 








64 15 35. 20 


22 


-.017 


17.792 


.157 


— .10 


K 


378 


c 




54 14 


3. 10 


— 3 1 24.71 


30 


— .068 


17.613 


.223 


+ . 11 




379 






55 29 


1.67 


65 25 6. 34 


40 


.000 


17.560 


.125 


+ .16 


B 


380 






.56 


2.90 


9 25 3. 00 


31 


+ .020 


17.539 


.217 


— .10 


C 


381 






14 5 26 


1.87 


59 50 57.60 


26 


- .049 


17.124 


.150 


.00 


B 


382 


4,713 4 




6 48 


2.71 


2 55 4. 85 


34 


— .020 


17. 061 


.240 


-.15 


A 


383 


4,724 1 . 




9 34 


2.94 


10 36 33. 89 


25 


-.15) 


16. 933 


.238 


+ .11 


A 


384 


4,741 4 




12 17 


2.28 


46 35 3.56 


24 


+ . 151 


16. 804 


.191 


+ .04 


A 


385 


4,742 1 4 




12 20 


2.13 


51 51 55. 60 


16 


+ .085 


16.801 


.178 


+ .10 


A 


386 


4,753 . 




14 39 


2.84 


16 48 6. 57 


17 


+ .058 


16. 691 


.238 


+ .03 


B 


387 
388 






17 44 

27 11 


3.05 
2.59 


1 44 51. 76 
30 50 44. 36 


34 
16 


-.475 

+ .125 


16. 539 
16.058 


.259 
.234 


— .26 
+ .04 


4,808 S 


B 
B 


390 






28 47 

29 36 


1.62 
2.54 


60 42 5.76 
33 29.79 


20 
26 


+ .010 


15. 974 
15. 931 


.152 


+ .04 

-f .21 


4,820 '• e 


A 


391 


4,843 [ 5 




14 34 49 


2.23 


44 52 14.25 


21 


-.049 


15. 049 


.211 


+ .05 


B 


393 


! 5 




35 28 


2.73 


22 26 20. 13 


34 


+ .080 


15.614 


.257 


— .23 


B 


393 


4.870 ' 5 




39 33 


2.33 


40 54 58.60 


36 


+ .020 


15. 380 


.225 


— .10 


A 


394 


4,873 j 4 




40 12 


2.80 


17 25 18. 38 


27 


— .052 


15. 350 


.270 


+ .02 


B 


395 


1 J 




43 36 


2.67 


24 48 55.30 


34 


+ .035 


15.157 


.262 


.00 


A 


396 


4.903 i 5 




45 28 


2.14 


46 33 58.48 




-!o98 


15. 050 


.212 


+ .02 


B 


397 


4,906 1 5 




46 14 


2.37 


37 42 55. 09 


23 


+ .100 


15. 005 


.237 


— .59 


B 


308 


4,918 i 5 




48 42 


1.52 


59 43 58. 80 


19 


+ .140 


14.861 


.156 


.00 


B 


399 


4,933 1 5 




52 10 


2.80 


16 49 23. 39 


30 


.000 


14. 656 


.285 




A 


400 


4,9D1 1 4 




57 27 


3.03 


2 30 56.45 


25 


+ .010 


14.337 


.315 


+ .00 


B 


401 


4,967 5 




14 58 55 


1.40 


60 37 44.43 


32 


+ .027 


14. 246 


.150 


— ..33 


A 


402 


5,031 1 5 




15 9 08 


2.51 


29 33 55. 16 


23 


+ .033 


13.549 


.276 


+ .04 


B 


403 


5,033 1 e 




10 16 


2.16 


42 34 24.70 


36 


— .025 


13.530 


.239 


.00 


B 


404 


5,048 5 




13 34 


2 69 


20 58 4. 30 


33 


— .012 


13.316 


.298 


+ .10 


A 


405 


5,061 5 




15 40 


2.48 


30 29. 01 


19 


-.049 


13. 177 


.280 


— .01 


A 


400 


5,072 1 5 




17 29 


2.40 


33 19 12.91 


20 


+ .004 


13. 057 


.272 


— .01 


A 


407 


5,085 5 




20 47 


2.78 


15 48 29.54 


21 


+ .005 


12. 837 


.317 


+ .00 


B 


408 


5,091 '• 5 




20 50 


.99 


63 43 37. 51 


31 


— .090 


12.834 


.116 


+ .09 


B 


409 


5,113 1 e 




25 57 


1.91 


48 5 2.80 


33 


-.010 


12. 486 


.224 


+ .40 


A 




5,119 5 




27 24 


3.08 


— D 49 10. 85 


30 


— .046 


12.387 


.359 


+ .05 


B 


«1 


5. 147 5 




15 29 25 


.84 


64 34 19.31 


18 


+ .078 


12. 248 


.103 


— .31 


B 


412 


5, 152 6 




31 28 


2.78 


15 27 31.83 


26 


+ .013 


12. 105 


.328 


+ .17 


B 


413 


5, 153 5 




31 31 


2.76 


16 28 36.90 


33 


.000 


12. 102 


.326 


+ .00 


B 


414 


5, 177 5 




34 49 


1.91 


47 9 13. 29 


31 


- .133 


11.871 


.229 


+ .11 


A 


415 


5,214 4 




41 12 


2.91 


7 4130.21 


28 


-.057 


11.416 


.356 


+ .29 


A 


416 


5, 244 4 




45 4 


2.51 


26 23 56.98 


21 


— .078 


11. 136 


.311 


+ .02 


B 


417 


5,248 5 




45 1 


1.44 


55 42 27.24 


28 


+ .010 


11. 139 


.179 


H- .06 


A 


418 


5, 259 4 




47 1(1 


2. 26 


35 59 33. 04 


23 


— .357 


10. 983 


.280 


+ .06 


B 


419 


5.273 e 




49 40 


2.05 


20 37 39. 99 


34 


+ .047 


10.788 


.330 


+ .21 


A 


420 


5, 284 3 




51 28 


2.76 


16 51.73 


13 


-1.286 


10.666 


.343 


— .03 


B 


421 


5,298 5 




15 51 52 


2.02 


42 52 49.22 


20 


.000 


10.630 


.254 


-.12 I 


B 


422 


5.3,3 5 




55 14 


1.41 


55 3 18.23 


26 


+ .118 


10.386 


.183 


— .23 


A 


423 


5.338 1 4 




.59 26 


1.87 


46 20 11.81 


19 


-.064 


10.069 


.239 


-f .09 


A 


424 


5, 366 6 




IB 3 10 


2.89 


8 49 18.02 


30 


— . 012 


9.778 


.372 


.00 


A 


425 1. 


ec5,367 6 




3 12 


2.70 


17 20 .5.44 


18 


— .011 


9.783 


.350 


+ .00 


A 


420 


5, 388 4 




5 22 . 


1.89 


45 13 5.51 


17 


H- .043 


9.617 


.246 


— .01 


A 


427 


5, 411 5 




7 51 


2.19 


30 42 14.50 


24 


— .040 


9. 426 


.286 


.00 


A 


428 


5,448 6 




13 55 


2.48 


26 9 35.06 


29 


-.007 


8.954 


.327 


+ .01 



UNITED STATES AND MEXICAN BOUNDARY. 
Mean declinations of latitude stars— Coutimied. 



45 



Class. 


.0. 


B. A. C. 


Mag. 


AK. 1892. 


Annual 
variation. 


Declination, ^™'' 
1892. «^ 


!;J?'® I'roper 
2.' '"»«»"■ 


5? 


Sec. var. 


" 










;.. m. s. 


s. 


. „ 






„ 




„ 


A 


429 


5,456 


5.0 


16 36 


+ 3.03 


116 58.91 ±0 


26 


+0.035 


—8.743 


+0.404 


+0 


09 


A 


430 


5,512 


2.7 


22 32 


.81 


6145 31.15 


15 


+ .050 


8.273 


.110 




05 


A 


431 


5,545 


5.0 


16 28 12 


- .15 


69 6.47 


14 


+ .030 


7.820 


- .014 


I 


07 


B 


432 




0.1 


32 14 


+3.21 
1.63 


— 6 19 12.82 


40 
20 


-.010 
+ .021 


7.493 
7.201 


+ .438 
.225 


J 


02 
10 


A 




5,596 


5.0 


35 49 


49 8 22.74 


+ 


B 


434 




0.3 


43 10 


2.76 


13 46 57. 25 


29 


— .010 


6.597 
6.480 


.385 


: 


23 


B 


435 


5,647 


5.9 


44 36 


2.77 


13 27 0. 03 


31 


- .008 


A 


436 


5,693 


5.5 


48 52 


2.27 


31 52 50. 33 


20 


— .019 


6.124 


.319 


_ 


03 


A 


437 


5,731 


3.7 


56 9 


2.29 


31 5 8.41 


16 


+ .032 


5.514 


.324 


_ 


01 


B 


438 




5.0 


17 1 44 


2.54 


22 13 50. 04 


30 


.- .045 


5.043 


.302 


+ 


10 


B 


439 


5,790 


0.1 


4 15 


1.95 


40 39 20. 21 


22 


— .031 


4.830 


.279 


_ 


11 


A 


440 


5,828 


3.1 


lU 36 


2.46 


24 58 0.58 


18 


— .153 


4.289 


.354 


+ 


02 


A 


441 


5,847 


4.8 


17 13 57 


2.07 


37 24 17. 73 


18 


+ .084 


4.003 


.208 




03 


A 


442 


5,871 


5.7 


17 18 


1.70 


40 20 48. 07 


19 


+ .032 


3.715 


.245 


+ 


13 


B 


443 




5.8 


19 41 


2.68 


16 24 2. 76 


24 


— .040 


3.509 


.388 
.112 




30 
46 


B 


444 


5,917 


5.7 


2t 18 


.77 


60 8 21. 14 


27 


+ .070 


3. 112 


; 


B 


445 


5,919 


5.8 


25 56 


3.01 


2 48 21.40 


25 


+ .032 


2.969 


.436 




30 


B 


446 


5,944 


5.9 


29 42 


2.70 


41 19 11.89 


34 


- .060 


2.644 


.277 


_ 


29 


B 


447 










21 3 50. 24 
48 38 54. 59 


34 
22 


-.024? 
+ .051 


2.498 
2.287 


.372 
.228 




34 
11 


A 


448 


5,075 


5.8 


33 48 


1.56 


+ 


B 


449 












44 
13 


+ .010 
— .268 


1.411 


.398 
— .157 




14 

02 


A 


450 


6,047 


4.5 


17 43 51 


-1.08 


72 12 6. 18 


+ 


A 


451 


6,078 


3.5 


53 5 


-r3.30 


- 9 45 35.45 


13 


— .105 


.605 


+ .482 


+ 


05 


A 


452 


6, 142 


4.9 


18 2 8 


2.87 


8 43 13. 49 


28 


+ .033 


+ .187 


.418 


_ 


09 


A 


453 


0,157 


4.4 


4 8 


2.50 


20 47 51. 68 


25 


— .013 


.362 


.374 


_ 


08 


B 


454 


6,185 


0.0 


8 10 


1.22 


54 15 15.70 


23 


+ .245 


.727 


.177 


_ 


10 


B 


455 


6,203 


5.4 


12 17 


1.86 


42 7 21.39 


19 


.000 


1.074 


.271 


+ 


01 


B 


456 


6,218 


0.0 


13 41 


1.92 


40 53 39. 20 


31 


+ .079 


1.197 


.279 




10 


A 


457 


6,221 


5.5' 


15 44 


2.53 


21 54 50.69 


26 


-.051 


1.375 


.369 


+ 


01 


A 


458 


0,241 


0.1 


17 38 


2.50 


23 13 50.40 


21 


-r .082 


1.542 


.263 




00 


A 


459 


C.251 


4.1 


19 6 


2.55 


21 43 14.97 


15 


-.257 


1.069 


.369 


+ 




A 


460 


6,208 


5.0 


20 40 


1.97 


39 26 54.48 


21 


— .001 


1.806 


.286 




08 


A 


461 


0,297 


4.4 


18 22 18 


- .85 


71 16 48.57 


13 


+ .021 


1.949 


- . 125 


+ 


03 


A 


462 




4.1 


29 20 


+3.20 


— 8 19 9.02 


14 


— .307 


2.550 


1- .472 


^_ 


C2 


B 


403 


0,373 


0.7 


37 


.73 


00 30 38. 83 


28 


+ .053 


3.231 


.104 


+ 


47 


A 


464 


6,379 


5.1 


39 23 


3.03 


1 57 1.32 


25 


— .026 


3.429 


.434 


+ 


03 


B 


465 


6,404 


5.9 


42 46 


1.92 


41 19 32. 92 


28 


+ .003 


3.720 


.273 




38 


B 


466 


0,428 


5.9 


45 25 


1.58 


48 37 38. 50 


19 


+ .053 


3.948 


.225 




00 


B 


467 




6.1 


47 5 


2.75 
2.50 


13 50 12. 52 
21 17 43. 02 


33 

25 


— .010 

— .006 


4.091 
4.140 


.390 
.364 




52 
02 


A 


468 




0,438 


5.3 


47 40 




A 


409 


6,466 


4.4 


50 44 


2.10 


36 45 42. U 


24 


+ .020 


4.402 


.297 


_ 


04 


B 


470 


0.476 


5.8 


51 50 


1.59 


48 43 27. 50 


34 


— .133 


4.506 


.224 


_ 


30 


B 


471 




5.8 


18 .15 21 


2.44 


20 4 53. 11 


31 


— .003 


4.797 


.342 


_ 


31 


A 


472 


0,528 


3.1 


19 27 


2.75 


13 42 11.54 


17 


— ■ . 089 


5.228 


.386 


_ 


04 


A 


473 


6,552 


5.4 


3 42 


2.94 


5 54 13.83 


22 


— .064 


5.503 


.410 


_ 


03 


A 


474 


6,583 


5.4 


9 38 


1.13 


56 40 30. f8 


15 


+ .045 


5.999 


.155 


+ 


02 


B 


475 


6,002 


5.8 


13 9 


2.54 


22 49 52. 35 


31 


— .011 


6.203 


.349 


_ 


23 


B 


476 


6,624 


5.4 


15 21 


1.38 


40 9 40.49 


31 


+ .005 


6.475 


.274 


_ 


09 


A 


477 


6,637 


5.4 


18 26 


2.46 


20 3 19. 15 


21 


- .013 


6.720 


.335 


+ 


05 


A 


478 


6,602 


4.0 


20 7 


.32 


65 30 23.57 


15 


+ .030 


6.868 


.041 


_(. 


03 


B 


479 


6,651 


6.7 


20 14 


2.15 


30 14 19. 39 


44 


+ .084 


6.677 


.292 


_ 


39 


A 


480 


0.674 


4.5 


21 13 


2.49 


24 26 47.26 


17 


— .102 


7.203 


.338 


_ 


06 


A 


481 


6.679 


5.4 


19 25 1 


3.14 


— 3 48. 78 


15 


+ .004 


7.269 


.424 


— 


02 


B 


482 


6,7U 


O.G 


29 51 


2.09 


38 31 37. 13 


32 


+ .037 


7.661 


.280 


_ 


23 


B 


483 


0,723 


5.8 


31 32 


1. i,5 


51 17. 87 


16 


— .190 


7. 708 


.205 


— 


17 


A 


484 


0,734 


4.7 


33 33 


1.01 


49 58 15. 82 


13 


+ .239 


7.900 


.214 


+ 


08 


A 


485 


6,739 


4.4 


35 10 


2.68 


17 45 56. 89 


22 


— .012 


8.098 


.355 


_i_ 


11 


A 


486 


0,749 


5.7 


37 29 


2.82 


11 34 21.73 


21 


+ .017 


8.275 


.372 


+ 


17 


A 


4S7 


6,759 


6.2 


39 33 


2.79 


13 2 37.91 


32 


— .017 


8.439 


.368 


_ 


01 


^ 


488 


0,779 


3.0 


41 36 


1.88 


44 52 1. 90 


15 


+ .035 


8.601 


.363 


+ 


10 




489 


0,805 


5.6 


45 51 


2.86 


10 8 44. 10 


24 


— .149 


8.936 


.369 


+ 


10 



46 



UNITED STATES AND MEXICAN BOUNDARY. 

Miiin decUiiatiuns of lalitude s/((i-s— Continued. 



0>a.. 


No. 


B.A.C. 


Mag. 


AE.1892. 


Annual 
variation. 


Beolination, ^"j! 

1892. f^, 


able 
or, 

2. 


^IZl 


Annual 
preces- Sec 
sion. 


W. 


A5 


A 


490 


6,B24 


5.3 


h. m. s. 
47 55 


+ 1.51 


52 42 50. ,57 +0 


22 


—0 


075 


+ 9.097 +0 


190 


+0.03 


B 

A 


491 
492 




0.3 
5.2 


19 48 
52 


2.99 
2.14 


4 7 16. 09 
38 11 59.30 


37 
19 


+ 


020 
007 


9.104 
9.414 


385 

274 


+ .11 
.00 


6,849 


B 


493 


6,807 


5.4 


53 52 


1.15 


58 33 27.41 


19 


_ 


018 


9.558 


144 


— .01 


B 
A 


494 
495 




5.8 


54 21 
57 10 


2.38 
2.54 


30 4127.44 
24 30 3.46 


29 
14 


+ 


006 
001 


9.595 
9.811 


300 
318 


— .44 

— .06 


6,882 


A 


496 


6,883 


5.4 


57 20 


2.54 


24 38 8.49 


23 


+ 


001 


9. 832 


318 


+ .01 


A 


497 


6,893 


5.8 


58 52 


2.93 


6 58 24.84 


21 


+ 


036 


9.940 


317 


+ .06 


B 

B 


498 
499 




5.8 
6.3 


20 22 

2 54 


2.35 
1.36 


31 54 45 38 
56 1 44. 30 


30 
22 


+ 


006 
068 


10. 054 
10.246 


293 

167 


— .08 
+ .40 


6,924 


B 


500 


6,930 


6.1 


3 23 


.76 


03 34 45.99 


32 


+ 


043 


10. 282 


091 


+ .01 


A 


601 


6,937 


5.2 


20 5 25 • 


2.23 


36 31 in. 05 


21 


+ 


050 


10.437 


272 


+ .05 


A 


502 


0,934 


3.1 


5 44 


3.10 


- 1 8 29.64 


12 


+ 


014 


10. 457 


380 


— .06 


A 


503 


6,944 


0.0 


7 29 


2 61 


26 9 23. 08 


24 


— 


027 


10. .588 


308 


— .08 


A 


501 


6,952 


5.1 


9 17 


2.78 


14 52 8.06 


19 


+ 


081 


10. 721 


337 


— .CO 


B 


505 


6,966 


5.0 


10 41 


2.54 


25 16 44. 06 


31 


_ 


015 


10. 825 


307 


— .35 


A 


506 


6,968 


5.0 


10 50 


2.59 


23 10 43. 94 


31 


_ 


014 


10.836 


314 


— .04 


A 


507 


6,983 


4.5 


12 8 


1.85 


47 22 67. 16 


19 


— 


008 


10. 931 


222 


+ .04 


A 


508 


6,990 


var. 


13 48 


2.21 


37 41 49. 81 


25 


+ 


003 


11.064 


264 


+ .09 


B 


509 


7,017 


6.0 


16 28 


.61 


66 30 23 27 


23 


+ 


284 


11.247 


059 


— .17 


A 


510 


7,024 


5.8 


17 48 


1.01 


61 54 52. 18 


20 


+ 


Oil 


11. 344 


117 


— .08 


A 


511 


7, 022 


2.6 


20 18 21 


2. 15 


39 54 40.33 


13 


+ 


020 


11.383 


254 


— .03 


A 
A 


512 
513 




6.2 
6.1 


19 7 
22 46 


3.06 
3.14 


43 9.27 
— 3 42 51.33 


27 
20 


+ 


006 
005 


11. 439 


361 
368 


— .17 

— .07 


7,016 


A 


514 


7,085 


5,0 


26 43 


1.86 


48 35 19.01 


19 


+ 


007 


11.978 


212 


— .01 


A 


515 


7,098 


4.0 


27 46 


1.02 


02 37 51. 79 


14 


_ 


027 


12.052 


113 


+ .01 


j^^ 


510 


7,091 


5.0 


27 59 


1.85 


48 51 20.71 


20 


_ 


040 


12.067 


211 


+ .09 


A 


517 


7,107 


4.7 


30 16 


2.80 


14 18 0.46 


21 


_ 


002 


12. 225 


319 


+ .04 


A 


r,is 


7,121 


3.5 


32 29 


2.81 


14 13 10 62 


17 


_ 


031 


12. 379 


317 


.— -02 


A 


519 


7.137 ■ 


6.0 


33 38 


2.83 


12 56 9. 83 


27 


_ 


006 


12.458 


319 


— .03 


B 


520 


7, i:i8 


5.3 


33 53 


3.07 


6 25. 35 


22 


_ 


010 


12.475 


346 


- .03 


A 


521 


7,182 


5.5 


20 38 53 


1.85 


49 57 8. 02 


19 


_ 


002 


12. 815 


202 


— .t2 


B 


522 


7,189 


6.9 


39 36 


1.49 


56 59 47. 97 


31 


_ 


022 


12.862 


160 


— .17 


A 


523 fc 


U 7,200 


3.9 


41 39 


2.78 


15 44 6.87 


18 


_ 


196 


13. 000 


304 


+ .03 


A 


524 


7,206 


5.7 


42 27 


2.97 


5 36 42. 13 


10 


+ 


001 


13. 053 


324 


+ .07 


A 


525 


7,213 


4.7 


43 12 


2.33 


36 5 38.42 


17 


+ 


018 


13. 103 


252 


— .02 


A 


526 


7,246 


4.9 


47 30 


2.57 


26 41 33.80 


21 


_ 


074 


13. 386 


274 


.00 


A 


527 


7,257 


5.6 


50 29 


2.86 


12 9 20.41 


21 


+ 


010 


13.579 


301 


+ .09 


B 


528 


7.268 


6.0 


52 11 


2.02 


47 13.83 


33 


+ 


004 


13.688 


210 


— .03 


B 


529 


7.278 


5.8 


53 


1.90 


50 18 50. 00 


31 




007 


13.740 


195 


.00 


A 


530 


7.276 


5.3 


53 41 


3.01 


3 52 46. 20 


21 


_ 


139 


13.783 


312 


— .10 


B 


531 




6.0 


20 55 32 ■ 


2.74 


18 54 35. 19 


34 


_ 


058 


13. 900 


2S2 


-.29 


B 


532 


7,310 


5.8 


50 46 


1.47 


59 59. 25 


14 


__ 


002 


13. 978 


148 


•1- .05 


A 


533 f. 


11 7,302 


6.4 


66 63 


2.96 


6 45 19. 94 


27 


_ 


012 


13.985 


300 


— .04 


B 
A 


534 

535 




5.9 
4.0 


69 10 
21 1 


1.65 
2.18 


56 14 35. 37 
43 29 49. 08 


20 
15 


- 


006 

008 


14. 128 
14.241 


164 
218 


+ .13 
+ .02 




7,333 


A 


530 


7,350 


4.5 


5 5 


2.95 


9 41 47.87 


21 


— 


167 


14.491 


288 


+ .03 


A 


537 


7,351 


6.1 


5 16 


2.95 


9 36 30. 92 


24 


+ 


019 


14. 502 


288 


- .02 


B 


538 


7 365 


5.8 


6 55 


1.85 


53 7 19.84 


23 


_ 


014 


14. COl 


178 


— .04 


A 


539 


7^380 


4.1 


10 25 


3.00 


4 48 5. 47 


It 


_ 


078 


14.810 


2S8 


+ .03 


A 


540 


7,398 


4.5 


13 10 


2.35 


38 50 31. 32 


21 


_ 


013 


14.971 


222 


+ .08 


B 


541 


7,402 


5.0 


21 14 25 


2.26 


43 29 29.52 


26 


_ 


012 


15. 043 


209 


+ .08 


B 


542 


7,410 


5.9 


16 11 


2.69 


23 24 4. 42 


28 


_ 


1.30 


15.145 


153 


— .42 


A 


543 


7,417 


5.9 


16 16 


1.66 


58 9 59. 35 


20 


_ 


024 


15. 150 


200 


— .05 


A 


544 


7,418 


4.3 


17 5 


2.77 


19 20 33. 38 


19 


+ 


075 


15. 196 


257 


+ .12 


]i 


545 


7,437 


5.8 


19 7 


2.69 


23 4S 37. 19 


28 


.)- 


030 


15.311 


247 


-.29 


A 


546 


7,440 


5.9 


19 39 


3.01 


— 4 1 11.00 


32 


_ 


068 


15. 347 


288 


— .30 


A 


547 


7,482 


5.0 


25 41 


1.71 


06 20 16. 04 


19 


_ 


042 


15.676 


100 


-.04 


B 
B 


548 
549 




6.0 
0.1 


25 56 
30 44 


2.90 
2.00 


11 39 47.20 
51 13 1.81 


24 


- 


004 
008 


15. 690 
15.948 


257 
176 


— .30 
+ .29 


7,512 


B 


,150 


7,528 


5.9 


33 59 


2.79 


19 46 41.55 


38 


4- 


006 


16. 119 


236 


— .16 


n 


551 


7,630 


6.1? 


21 34 3 


2.00 


53 33 21.21 


25 


_ 


018 


16.122 


167 


— .01 


A 


552 


7,542 


5.1 


35 1 


1.61 


61 35 41.19 


18 


- 


012 


16. 173 


132 


— .09 



UNITED STATES AND MEXICAN BOUNDARY. 
Mean declinations of latitude stars— Continned. 



47 



(JIass. 


No. 


B.A.C. 


Mag. 


AE.1892. 


Annual 
variation 


Declination, P™b\l"« 


SS. 


Annual 
preces- Sec 


var. 


A6 










h.m.s. 


,. 


o , „ 








„ 


„ 


A 


553 


7,544 


5.5 


35 57 


+ 2.35 


42 47 0.76 ±0 


18 


+0.0U 


+ 16.220 +0 


194 


+0.04 


A 


554 


7,546 


5.9 


36 40 


3.06 


47 36. 76 


20 


_ 


020 


16.257 


255 


_ 


26 


A 


555 


7,561 


2.4 


38 53 


2.95 


9 22 48.00 


17 


^ 


Oil 


16. 370 


241 




00 


B 


556 p 


r 7, 560 


5.6 


38 58 


2.47 


37 47 21.21 


22 


+ 


001 


16.374 


201 


_ 


11 


B 


657 


7.586 


6.8 


41 29 


2.72 


25 3 48.33 


38 


+ 


038 


16. 500 


218 


+ 


17 


A 


558 


7,587 


5.6 


41 45 


3.04 


2 11 11.80 


25 


_ 


010 


16.514 


245 




00 


A 


559 


7,605 


5.9 


44 14 


I 


77 


60 U 29.53 


28 


_ 


001 


16.636 


137 


_ 


03 


A 


*d60 


7,631 


6.0 


48 22 


1 


75 


55 17 20. 91 


32 


._ 


025 


16.835 


153 


_ 


31 


jj 


561 




6.4 


21 54 25 


1 


53 


65 38 27. 51 


30 


, 


003 


17. 117 


110 


_ 


11 


B 


562 




6.8 


54 38 




54 


65 37 24, 50 


30 




006 


17. 127 


110 




20 


A 


563 


7,660 


5.9 


55 34 


3 


07 


5 10. 85 


23 


_ 


001 


17. 169 


224 


4 


05 


A 


564 


7,662 


5.9 


55 48 


2 


98 


7 44 17. 02 


28 


_). 


005 


17.179 


217 


_ 


02 


A 


565 


7,672 


4.7 


57 44 


3 


10 


—2 40 35. 69 


21 


_ 


002 


17. 266 


222 


_ 


01 


A 


566 


7,685 


5.8 


59 14 


3 


09 


-1 25 42.43 


21 


_ 


031 


17. 333 


218 


4_ 


03 


B 


587 


7,699 


5.7 


22 39 


1 


79 


62 35 39. 31 


27 


+ 


034 


17. 394 


123 


+ 


29 


A 


568 1 


1.11 7,700 


4.6 


40 


1 


73 


64 6 5.57 


17 


4. 


065 


17. 395 


116 


4. 


03 


A 


569 


7,693 


5.7 


41 


2 


71 


28 26 21.53 


21 


_ 


010 


17.390 


189 


-f- 


07 


A 


570 


7,707 


5.8 


1 44 


1 


82 


62 15 31.46 


17 


+ 


045 


17.441 


124 


+ 


04 


B 


571 


7,733 


6.1 


22 5 24 


2 


83 


20 20 50. 16 


28 


_ 


008 


17. 598 


190 


_ 


26 


A 


572 


7,749 


3.7 


7 6 


2.07 


57 40 8.01 


15 


_ 


006 


17.669 


135 


_ 


01 


B 


573 


7, 753 


5.6 


8 1 


2.65 


34 419.97 


30 


_ 


041 


17. 706 


173 


— 


27 


B 


574 


7,770 


5.8 


10 12 


2.51 


42 25 5.58 


25 


_ 


020 


17. 795 


161 


_ 


08 


A 


575 


7,788 


5.5 


15 1 


3.02 


6 14 48. 43 


20 


_ 


005 


17. 986 


187 


— 


03 


A 


576 


7,795 


3.7 


16 5 


3.10 


-1 55 63. 27 


13 


+ 


017 


18. 026 


190 


_ 


03 


A 


577 


7,807 


0.1 


18 28 


2.86 


20 18 9. 17 


20 


_ 


019 


18. 117 


171 


_( 


13 


A 


578 


7,837 


5.7 


23 37 


1.91 


64 34 53. 59 


25 


_ 


012 


18. 305 


106 


+ 


01 


I! 


579 


7,850 


4.8 


25 50 


2.09 


42 34 11. 16 


27 


_ 


002 


18.384 


143 


_ 


00 




580 


7,868 


4.0 


29 48 


3.08 


—0 40 26, 85 


12 


_ 


053 


18.520 


164 


+ 


05 


A 


581 


7,893 


5.9 


22 33 30 


2.90 


18. 57 48. 21 


23 


^ 


094 


18.646 


148 


+ 


09 


A 


582 


7,902 


5.3 


34 49 


2.11 


63 1 22. 83 


38 




039 


18.6S4 [ 


105 


— 


03 


A 


583 


7,906 


4.9 


35 47 


2.02 


43 42 44.52 


22 


_ 


016 


18.714 


129 


_ 


02 


B 


584 


7,931 


0.1 


39 13 


2.70 


38 53 58. 56 


25 


- 


030 


18 


820 


128 


_ 


06 


A 


585 


7,945 


4.0 


41 20 


2.88 


22 59 50. 53 


15 


_ 


004 


18 


883 


133 


_ 


03 


A 


580 


7,9.18 


3.8 


44 47 


2.89 


24 1 52.84 


10 


- 


042 


18 


983 


126 


- 


04 


1! 


587 


17, 903 


( 0.5 
I 7.0 


} 45 20 


2.01 


67 59 50. 52 


23 


+ 


069 


18 


998 


087 


- 


12 


]! 


588 


7,984 


5.9 


49 10 


2.73 


39 48 4. 20 


30 


+ 


039 


19 


103 


113 


_ 


70 


V. 


589 


7,980 


5.9 


49 35 


3.11 


-5 33 47.57 


22 




000 


19 


114 


129 


_ 


03 


A 


590 


7,993 


6.5 


61 42 


3.10 


—5 23 13. 91 


17 


+ 


005 


19 


169 


124 


+ 


01 


B 


591 


7,999 


.5.3 


22 52 18 


2.04 


48 6 24.78 


21 


_ 


030 


19 


184 


104 


+ 


02 


B 


592 


8,013 


6.7 


54 44 


2.44 


59 14 9.34 


24 


_ 


021 


19 


245 ] 


091 


— 


04 


A 


593 


8,031 


4.6 


58 23 


3.05 


3 14 18.50 


20 


_ 


015 


19 


332 


110 




00 


A 


594 


8,034 


2.2 


69 23 


2.98 


14 37 27. 23 


16 


_ 


030 


19 


355 


105 


+ 


07 


B 


595 


8,077 


6.4 


23 6 40 


2.34 


66 39 21.14 


33 


Jf. 


022 


19 


492 


073 


+ 


36 


B 


596 


8,094 


5.4 


10 


3.09 


—4 5 0.53 


28 


+ 


005 


19 


578 


089 


- 


07 


A 


597 


8.105 


3.8 


1134 


3.10 


2 41 31.76 


13 


4. 


017 


19 


607 


065 


+ 


04 


B 


598 




6.7 


15 34 


2.63 


59 41 0.43 


33 




031 


19 


677 


084 


_ 


13 




599 


8,158 


6.9 


19 13 


2.71 


50 56 33. 05 


23 


_ 


013 


19 


736 


061 


+ 


05 


A 


600 


8,162 


5.5 


20 2 


2.64 


61 41 23.38 


15 


— 


021 


19 


749 


058 


+ 


02 


A 


601 


8,169 


5.0 


23 21 24 


3.07 


39 51. 60 


15 


_ 


102 


19 


769 


066 


_ 


10 


A 


602 


8,177 


4.5 


22 29 


3.07 


5 47 8.77 


18 


_ 


045 


19 


785 


064 


_ 


07 


B 


003 


8,188 


5.0 


25 3 


2.75 


57 57 12.92 


28 


+ 


003 


19 


820 


052 


— 


12 


A 


604 


8,195 


5.7 


25 59 


2.94 


38 38 34.48 


15 


_ 


077 


19 


832 


054 


+ 


02 


B 


005 




6.1 


28 30 


3.00 


20 14 40. 94 


31 


_ 


014 


19 


864 


062 


_ 


24 


B 
A 


606 
007 




6.3 
4.1 


30 32 
32 50 


2.99 
2.93 


23 57 47.44 
42 40 12.20 


31 
16 


- 


023 
012 


19 
19 


912 


048 
042 


+ 


46 
00 


8,229 


A 


608 


8,233 


4.2 


34 24 


3.08 


5 2 27.02 


14 


_ 


443 


19 


928 


040 


_ 


02 


A 


609 


8,243 


4.8 


36 32 


3.06 


1 11 8.42 


19 


_ 


137 


19 


948 


038 


_ 


02 


A 


610 


8,262 


5.7 


40 52 


3.06 


2 53 16.02 


18 


_ 


023 


19 


983 


029 


+ 


08 


A 


_^ 


8,279 


5.8 


23 43 36 


-2.89 


61 36 61.20 


19 


- 


010 


20 


001 


022 




00 



t Middle point botv 



48 



UNITED STATES AND MEXICAN BOUNDARY. 
Mean declinations of latitude stars — Continued. 



Class. 


No. 


B.A.C. 


Ma. 


AR. 1892. 


Annual 
variation. 


Declination, 
1892. 


Probable 
1892.' 


,^S 


Annual 


Sec. var. .i 


S 








h. m. .1. 


e. 


o , .. 




„ 


„ 


„ 




B 


(-.12 


8,280 


6,5 


43 36 


+2.91 


59 22 41. 61 


+0.23 


—0. 003 


+ 20.002 


+ 0.021 — 


01 


A 


ei3 


8,295 


5.9 


46 26 


3.07 


2 19 47.80 


.19 


— .011 


20. 018 


+ .018 


00 


A 


6U 


8,296 


5.9 


46 54 


3.04 


21 4 13.40 


.26 


- .018 


20. 020 


+ .018 + 


10 


". 


615 
616 




6.0 


48 28 
50 6 


3.06 


00 15 9.10 
7 37 20. 34 


.30 


— .006 

- .007 


20. 027 
20. 034 


+ .014 

+ .010 — 


00 
04 


8,315 


B 


617 


S,322 


5.8 


51 42 


3.00 


55 17.11 


.19 


— .024 


20. 040 


+ .007 — 


31 


A 


618 


8,330 


5.0 


53 32 


3.01 


55 9 13. 44 


.20 


-.015 


20. 045 


+ .004 - 


04 


li 


619 


8,345 


6.0 


56 12 


3.05 


41 45 50. 51 


.35 


— .016 


20.050 


0.0 - 


01 


A 


620 


8,354 


5.0 


56 58 


+3.06 


7 53 8. 39 


.21 


— .027 


20. 051 


-.002 + 


01 


B 


621 




6.3 


23 57 41 


+3.07 


10 57 8. 86 


.27 


-.037 


+ 20.052 


—.004 — 


30 





Authorities for star cataloyue. 

First column : Number in catalogue. 

Second colunni: Authority for proper motion. — "Brad. 11'" denotes, for example, tli.at the Proper Motions are from Auwers's liradley. and that 
Bradley has eleven observations. "Piazzi and others'' denotes that all available observations including and since Piazzi have been used. 
No statement in column 2 denotes in general that the old observations are rather scanty, chiefly zones. 

Tliird column : Authorities used in the star iilaces em]doyed on the boundary. — They jire alil)reviations of the names of the observatories, 
witb dates, in 1800- 190U. "Xrnl." denotes Yarnalls' Catalogue, 3d edition. For Oxford, Greenwich, Washington, the observations not 
yet catalogued have been previously reduced to some mean epoch; for example. No. 002 (.V.X. .\m. Ephemeris star) was on revision 
brought up from Washington volumes for many years to tlie mean epoch 1876, 1884, and tlio Gri'eiiwich volumes for 1887-1890 wore simi- 
larly treated. 

Fourth column : Observations added on revision. 



No. 


Authorities for 
proper motion. 


Authorities used for declinations in computing latitudes on the 
boundary. 


Observations added 
on revision. 












Bradley 7 


Berlin Jahrbuch, Pulk. 55, Oxford 60, Cambridge. Rome, Pu'k. 75, 








Grnwch. 80. 






Bradley 5 


Pulk. 55, Paris 60, Glasgow, Brussels, Grnwch.64,72,80, Leijizig, Leiden, 
Rome. 














Pulk. 56, Brsls., Paris 75. Grnwch. 80, 89 






Bradley 5 


Pulk. 55, Yarnall, Oxfrd. 60, Brsls., Grnwch. 72, 80, Camhr., Paris 75, 
Rome, Pulk. 75. 






Arglndr. 3-250... 


Paris 00, 75, Bonn, Pulk. 62, 75, Trul., Grnwch. 04, Kdinboro, Glsgw., 
Melbourne, Albany Zone, Gotha. 






















Brad, aud later 
auths. 


Ednbro., Brsls., Pulk, 55, Oxfrd. 70, Grnwch. 72, A. G. Christiania Z 






Br.id. 5 


Paris 45, 00, Grnwch. 00, 72, 80, 87, Pulk. 55, Cambr., Rome, A. G. Hel- 
singfors, Gotha. 








Pulk. 55, 02, 75, Grnwch. 00, 64, 72, 80, 88. Brsls., Trnl., Paris 75, Glsgw., 
A.G.Albny.,Rome. 












Brill 1 






13 ' End 4 


Pulk 55 V'rnl Grnwch 64 72 89 Paris 75 Rome 




14 1 Br.id. 11 


Brln. .Jrbh.. Pulk. 55, 75, Oxfrd. 60, Yrnl., Paris 60, 75. Glasgow, Grnwch. 
80, 88, Auwers's 303 Stars Auwers's 






















'l auths. 














auths. 
















Brad. 14 


Pulk. 55, Paris 60, Yrnl., Grnwch. 64, 72, 80, 89, Brsls., Gilttingen, Glsgw., 








Paris 75, Auwers's 303 Stars. 




21 


Brad. 15 ... 


Brln. Jrbh., Yrnl., Oxfrd. 60, Paris 60, 75, Glsgw., Cambr., Pulk. 75, 








Rome, Grnwch. 80, 88. 












23 


Brad. 


Pulk. 55, Bonn, Grnwch. 64, 72, Lpzg., Leidn., Cambr., Rome, Paris 75 




24 


Brad. Land later.. 


Pulk. 55, Rome, Oxfrd. 70, Brsls., A. G. Helsingfors, Grnwch. 72, Berlin . . 





UNITED STATES AND MEXICAN BOUNDARY 
Authorities for star catalogue — Continued. 



49 



I Autliorites for 
liiojier motion. 



Authorities used for declinations in i 
boundary. 



27 Brad. . 

28 : Brail. 3 . 

29 Brad. 3 . 

30 Brad. 3 . 



31 Brad. 8 

32 Piazzi and others 
Brad. 10 



Brad.3 

Brad.4 

Brad. 1 and later. . 
Brad. (Auwer's) 
and others. 

I!rad.4 

Brad.l 



Auwers'sBradley. 



others. 
Brad. 4... 
43 I Bra<1.3... 



Pulk. 55, Ornwch. 60,72, Li)zg.,Leidn.,Eome :, 

Pulk. 55, Trnl., Ednbro., Grnivch. 64, Brsls 

Brlu.Jrbh.,Pulk.55, 75, Cambr., Rome, Paris 75 

Pulk. 55, Paris 60, Grnwch. 64, Glsgw. 75, Armagh 

Pulk. 55, Paris 60, Grnwch. 64, 72, 80, Rome 

Brln.Jrbh., Yml., lirsls., Canibr., Paris 75, Rome, Pulk. 75, Grnwch. 

80,88. 
Pulk. 55, Trnl., Grnwch. 60, 80, 88, A. G. Camlir., Paris 75, Rome, 

Gotha, Prime Vertical. 
Pulk. 55, Oxfrd. 60, Brsls., Trnl., Grnwch. 64, 72, Paris 60, 75, GLsgw., 

Rome, A. G. Albny., Gotha, Cincinnati. 
Brlu. Jrlili., Pulk. 55, 62, 75, Oxfrd. 60. Paris 60, 75, Trnl., Drsls., Glsgw., 

Rome, Grnwcli. 80, 89. 

Pulk. 55, Oxfrd. 60, Grnwch. 64, Brsls., Paris 75, Rome, Cinn 

Brlri. Jrbh., Pulk. 55, 75, Rome, Grnwch. 80 

Trnl., Glsgw., Pulk., Brsls., Grnwch. 72, Cambr., A. G. Albny 

Pulk. 55, Trnl., Oxfrd. 60, Brsls., A. G. Hlgfrs., Grnwch. 72, Rome, Brln . 



Pulk. 55, 75, Paris 60, Brsls., Glsgw., Grn wch. 64, 72, 80, Rome 

Brln. Jrbh., Oxfrd. 60, Paris 60, Tarnl., Brsls., Cambr., Rome, Pulk. 75, 
Grnwch. 80, 88, Rome. 

Pulk. 55, Grnwch. 72, A. G. Helsingfors, Pulk. 73 

Pulk. 55 Brsls., Paris 75, Grnwch. 80 



Brad.3. 
Brad.3. 



46 I Brad. 3 

47 ( Brad.4 

48 ■ Arglnd.and later 



Pulk. 55, Paris 75, Grnwch. 72, Rome, Cambr.. Ann Arbor, Grnwch. 80, 87 
Brln. Jrbh. , Oxfrd. 60, 75. Paris 60, 75, Trnl., Bonn, A. N., Washington 68, 

Boss, Glsgw., Cambr., Pulk. 75, Rome, Grnwch. 80, 89, Glasgow 90. 

Pulk. 55, 75, Oxfrd. 60, Paris 00, Grnwch. 64, 88, Brsls., Rome 

Pulk. 55,75,Trul.,Oxfrd. 60, Paris 75, Brsls., Grnwch. 64,72, 80, 88, Glsgw., 

A. G. Albny. 

Pulk. 55, Oxfrd. 60, Grn wch. 64, 80, Brsls., Rome, Paris 75 

Pulk. 55, Brsls., Grnwch. 04, 72, 80, A. G. Christiania., Rome 

Bonn, Brsls. A. G. Chrstana., Pulk. 75, Cinn 



■I Brad. 5 
Brad.O 



Pulk. 55. Grnwch. 04, Brsls., Rome, Paris 82, Grnwch. 87 

^'"'"'- 5 ' Oxfrd. 60, Brsls., Pulk. 55. Grnwch. 64, 80, 89, Rome. A. G. Helsin"for.s 

Brad.l ] Pulk. 55, Grnwch. 64, Rome ° 

^™'- Smwch. 60, 64, 72, Oxfrd. 60, Pulk. 55, 75, Braid., Giittingen, Cor- 
doba, Pulk. 75, Paris 75, Glsgw., Karlsruhe. 

Pulk. 55, Paris OO.Oxfrd. 60, Brsls.,Grnwch.64,Trnl.,Auwers's303 Stars 

Pulk. 55, 62, Grnwch. 60, 64, 72, 80, 88, Trnl., Brsls., Paris 75, A.G. Albny., 

^r-ii.l I Oxfrd. 60, Pulk. 55, Grnwch. 64, Brsls., A.G. Helsingfors 

^"•ad-S-- Pult. 55, Paris 60, 75, Grnwch. 64, Oxfrd. 65, Rome ..."^ 

^'''"l-ll rulk.55,75, Grnwch. 60, 64, 72, 80, Paris 60, 82, Trnl., Rome 

^'^'^- ^ r""'- 55, Trnl., Pulk. 62, Grnwch. 64,Gottingen, Paris 75,Cordoba,"K3rls. 

35rad.4 Pulk. 5-,, Oxfrd. 60, Brsls., Grnwch. 64, Rome 

' Pulk. 55, Paris 75. Grnwch. 80 

Brad.l5 1 Brln. Jrbh., Oxfrd.60, Pjiria 

G rnwch. 80, Pulk. 90, 91 . 

I Tulk. 55, Grnwch. 60, 80, Paris 60, Glsgw., Rome 

^'''"'■5 Pulk. 55, Grnwch. 60, 64, 72, SO, Brsls., Paris 60, Trnl., Rome 

^'"'"l-S Pulk. 55, Grnwch. 60, 72, 80, Trnl., Brsls.. Paris 75 

Bri^- " Pulk. 55, 75, Oxfrd. 60, Brsls., Cambr., Komi 

Brad.7 .... 



Brsls., Trnl., Cambr., Rome, Pulk. 75, 



Paris 75, Grnwch. 80 

Pulk. 55, Grnwch. 64, 72, Rome, Paris T". 

B™'! * I'nlk. 55, Paris 60, 75, Grnwch. 04, 7.', i 

I'»lk. 55, Grnwch. 64, Glsgw., Pari,, T.i 

^rad. 8 Pulk. 55, 62, 75, Oxfrd. 60, Grnwch. CO, 

Glsgw., Rome. 

ii'-^^i Brln.Jrbh., Oxfrd. 60, Trnl., P.ari8 

Rome, Grnwch. 80, 88. 
Pulk- 55, 75, Grnwch. 64, 80, Br.sls., Paris, 75, Glsgw.. Ci 



. Glsgw. 90. 



. Trnl., Paris \ 



ilsgw., Cilmbr., 



50 



UNITED STATES AND MEXICAN BOUNDARY. 
Authorities for star cataloyue — Continued. 



No. 

72 

73 

74 
75 

76 
77 

78 
79 
80 

81 

82 

8:i 

84 

85 
86 

87 
88 

89 

90 
91 
92 
93 
94 
95 
96 
97 
98 
99 

100 

101 
102 
103 

104 
105 
100 
107 

108 
109 
110 
111 
112 
113 
114 

115 
116 
117 


Authorities for 
proper motion. 


Anthorities used for declinations in computing Latitudes on the 
boundary. 


Observations added 
ou revision. 




r«llj.55,A.G. Helsingfors. Kome, Brln., Grnweh. 80, Pulk. Prime Ver- 

tical. 
Paris 60, 75, Brsls., Oxfrd. 64. Yrnl., Glsgw.. Pulk. 75, Crnwch. 72, 

Gotha85,A.N. 
Pullr. 55, 75, Konigsb. 61, Bonn, Paris 75, BrsLs. 05, Cordoba, Grnwch, 80, 

Karlsruhe. 
Grnwch 60 80 Pulk 55, Brsls., Trnl., A. G. Hlgfr8.,Eome 


Pulk. 85. 

Glsgw. 90. 
Wushgln. I'HiiiB 


Piazzi.etc 




Brad 12 


Brln. Jrbh., Oxfrd. 60, Paris 60, 82, Brsla., Trnl. Cambr., Rome, Pulk. 75, 
Grnwch. 80, 88. 




Groombridge and 

others. 
Brad.6 

Piazziand others. 




Oxfrd. 60, Pulk. 55, Brsls., Grnwch. 64, 72, A. G. Chriatiania, Rome 

Paris 60, Brsls., Pulk. 75, Cambr., Ann A rbor, Grnwch. 80 

Brln. Jrbh., Pulk. 55, 62, 75, Oxfrd., Trnl., Paris, SO, 75, Glsgw., Cambr., 

Rome, Grnwch. 80, 88, Auwers's 303 Stars. 
Pulk. 55. 75, Paris 60, Grnwch. 60, 80, Oxfrd. 60, Brsls., Trnl., Rome 




Br.adlan<llater.. 


Brln. Jrbh., Oxfrd. 60, Trnl., Paris 60, 75, Brsls., Washgtu. (Boss), 68, 

Oxfrd. 75, Cambr., Pulk. 75, Eome, Grnwch. 80, 89. 
Trnl., Oxfrd. 60, Brsls., Grnwch. 64, 72, 80, Paris 60, Cambr.. Rome, 

Pulk. 75. 

Trnl., Pulk. 55, Ednbro., Grnwch. 64, Armagh 75, Cambr., Paris 82 

Brln. Jrbh., Oxfrd. 60, 75, Trnl., Brsls., Cambr., Rome, Pulk. 75, 

Grnwch. 80. 
Brln. Jrbh., Paris 60, 75, Brsls., Trnl., Eome, Pulk. 75, Grnwch. 80, 88 ... . 
Brln. Jrbh., Paris, 60, 75, Trnl., Pulk. 62, 75, Brsls., Oxfnl. 70, Glsgw., 

Kome. Albny., Auwers's 303 Stars. 
Trnl., Pulk, 55, 75, Glsgw., Oxfrd. 60, 75, Brsls., (Iruwcb. 04, 72, 80, Eon.e, 

Paris 75. 
Trnl., Pulk. 55, Oxfrd. 60, 75, Grnwch. 64, 72. 80, Brsls., Eome, Paris 75. . . . 


Piazziand others. 


Brad. 10 

Brad 3 


Brad.5 

Brad. 2 (confirmed) 
Brad 3 


Piazzi.etc 






Pulk. 55. Paris 60. 75, Rome. Berlin. A. G. Cambr., Grnwch, 80, 87 


Brad. 2 and later. - 


Pulk 55 75 Paris 60 75 Grnwch. 64, Brsls 


Brad 4 


Pulk. 55, Grnwch. 64, Paris 75, Brsla., Gottingen, Glagw., Cordoba 

Pulk. 55, Grnwch. 64, 89, Brsls., Gottingen, Paris 75, Auwerss 303 Stars . 








Brln. Jrbh., Trnl., Oxfrd. 60, Brsls., Paris 00, 75, Cambr., Pulk. 75, Eome, 

Grnwch. 80. 
Tml., Pulk. .■•.5, Grnwch. 64,88, Brsls., Eome. Paris 75 

Pulk. 55, Paris 60, 75, Grnwch. 60, 64, 72, 80, 88, Brsls., Trnl., Rome, Brln. . 








Br.Td. 1 and later 
auths. 


Pulk. 55, Trnl., Glsgw., Grnwch. 64, Paris 60, 75, Brsls., Oxfrd. 75, A. G. 
Leiden. 

Brln. Jrbh., Pulk. 55. 75. Cambr., Eome, Grnwch. 80 

Pulk. 53, 75, Oxfrd. 60, Paris 60, Grnwch. 64, 72, 80, 89, Eome 


Brad 3 






Pulk. 55, Paris 60, 75, Grnwch. 60, 64, 72, 80, 89, Brsls., Trnl., Washgtn. 08 
(Boss), 0.xfrd. 75, Kome. 




Brad 3 


Pulk 55 Brsls. Grnwch. 64 




Ednbro Brsls Pulk 55 Brln A G Helsinffors 






Brad.5 






Brad.6 


Brln. Jrbh., Pulk. 55, 75, Oxfrd. 60, Paris 60, Brsls.. Trnl., Armagh 75, 
. Grnwch. 80, 88, Rome. 








Pulk. 55, Paris 60. 75, Grwnch. 64, Gottingen, Tml., Glsgw., Cordoba.. 
Karlsruhe. 





UNITED STATES AND MEXICAN BOUNDARY. 

Authorilie.K for star catalogue — Continued. 



51 



No. 


Authorities for 
jiroper motion. 


Authorities used for declinations in computing latitudes on the 
boundary. 


Observations added 


118 




Pulk,55,Grnwch.60, 61, 72, 80, 88, Paris 60, 75, Oifrd. 60, Brsls., Trnl., 
Oxfrd.72,Glsgw.,Kome. 




119 


Bra.l.l(Auwer's) 
and B083. 


Brln. Jrbh,, Brsls., Trnl., Cambr., PlUk. 75, Kome, Grnwcb. 80, 88 








Pulk. 55, Paris 60, Brsls.,Gmwch. 64, 72, 80, 89, Trnl., Brln.. Rome.Glsgw . 
Pulk 55 Paris 60 Gmwch 64 Oxfrd 75 Brsls Gls^w 






Brad 3 








Brln. Jrbh., Oxfrd. CO, Paris 60, 75, Trnl., Glsgw., Cambr., Pulk. 75, Rome, 
Grnwcb. 80, 88. 


















124 


Bra,1.3 


Pulk. 55, 75, Brsls., Glsgw., Paris 60, 75, Grnwcb. 64, 72, 80, Rome 






Brad.3 










Grnwcb. 60, Pulk. 55, Oxfrd. 60, Glsgw., P.aris 60, Brsls. (Jordoba, Krisrbe 
(85), Cinn. 


Karlsruhe, 1889. 






127 


Brad. 2 .ind later 
auths. 


Paris 45, Oxfrd. 60, Brsls., Pulk. 55, Grnwcb. 64, 72, 80 llorpat, Dorpat. . . . 




128 


Brad. 5 


Brln Jrbb. Pulk. 55, 75 Oxfrd. 60, Paris 60, Brsls., Trul., Cambr , Rome 








Grnwcb. 80, 88. 














Groombridge and 
latr. autlis. 




tiCill. 
















132 


Brad.4 


Grnwcb. 60, 64, 89, Pulk. 55, 75, Rome 












134 


Brad 4 


Pulk. 55, Grnwcb. 60, 64, 72, 80, 89, Trnl., Oxfrd. 60, Paris 60, Brsls., 
Glsgw., Rome. 






135 


Brad.6 


Brin. Jrbh., Oxfrd. 60, Brsls., Paris 60, 75, Trnl., Pulk. 75, Rome, Grnwcb. 








80. 88. 




130 


Brad 3 


Pulk 55 Oxfrd CO Paris CO, Brsls Grnwcb 72 80 Rome 






Brad 4 






ns 












87, 89. 


lioal. 






Cinn. 








Brin. Jri)h , Trnl., Cambr., Rome, Pulk. 75, Paris 82, Grnwcb. 80, 88 

A.G. Cambr., Gotha,Pr.VrtcI. A.N 




141 


(iroombridgo and 






others. 






142 


Brad 5 


Pulk 55 75 Brsls Gmwch 64 72 80 Glsgw Paris 60 75 Trnl 




143 


Piazzi and others. 


Grnwcb. 60 rejected, about 5" in error, Oxfrd. 60, Paris 60, 75, Brsls., 
Glsgw., Brin. 85. 




144 


Groombriilge anil 


A.G. Cambr., Giittingen, Prime Verticil, Paris 75 






other.s. 








Groombridge and 
other.s. 












140 


Piazzi and others. 


Pulk. 55, A. G. Hlgirs., Brsls., Glsgw., Rome, Grnwcb. 80 












148 


Brad.4 


Brln. Jrbh., Oxfrd. 60, Paris 60, 75, Trnl., Brsls., Cambr., Rome, Pulk. 75. 


Cambr. 93. 






Grnwcb. 80. 






Brad 11 


Pulk. 55, 75, Gmwch. 60, 64, 80, Oxfrd. 60, Trnl., Paris 60, Brsls., Rome. . . . 










151 


Brad.4 


Pulk. 55, 75, Grnwcb. 64, 72, 80, 87, 89. Rome 




152 


Piazzi and others. 


Paris 60, 75, Tml., Oxfrd. 70, Glsgw., Grnwcb. 80, 89 




153 


Brad. 12 


Brln. Jrbh., Pulk. 55, 75, Oxfrd. 60, Trnl., Paris 60, 7.0, Cambr., Glsgw., 
Rome, Grnwcb. 80, 88. 










154 


Piazzi and others. 


Pulk. 55, Glsgw., Oxfrd. 65, Paris 75. Grnwcb. 80 


too late. 














Washgtn. 68 (Boss), Cambr., Rome. 






Brad.3 






157 


Brad 27 


Pulk 55 Bonn Gmwch 64 72 Lpzn- Leidn Rome 




158 


Piazzi and others. 


Pulk. 55, Glsgw., Brsls.. Paris 60, 75. Gmwch. 64, 72, 80, 87, Oxfrd. 75, 
A. G. Leiden, Rome. 




159 


Brad 4 











* The Greenwich result for 1860 for star 13.9 was corrected 1 



! of a letter from Mr. H. P. HoUis of the Royal Olis 



52 



UNITED STATES AND MEXICAN BOUNDARY. 
Atitliorities for star catalogue — Coutinued. 



No. 


Authorities for 
proper motion. 


Authorities used for declinations in computing latitudes on the 
boundary. 


Observations added 
on revision. 


160 

ICl 
162 
163 
164 

165 

166 
167 
168 
169 

170 
171 
172 
173 
174 
175 
176 
177 

178 

179 

180 

181 

182 

184 
185 

18C 

187 

188 
189 
190 

191 
192 

193 
194 
195 
196 

197 

198 
199 
200 

201 

202 


Brad.5 


Pnlk. 55, 75, Oxfrd. 60, Paris 60, Brsls., Cambr , A. G. Albany, Kome, 
Grnwch.88,Cinn. 

PuUi. 55, Grnwch. 60, 80, Glsgw., A. G. Albany, Rome 

Pulk. 55, 71, 75, 81 , Prime Vertical 91, Prime Vertical Cambr., YrnI 


Pulk. 68 Pr. Vrtcl. 
Karlsruhe. 

Cinn. 
Paris 70. 
Paris 60, 75. 
Paris OU.Gwcb. 87, 
88, Brln. 85. 


Argelander 


Groombridge and 

others. 
Brad 5 




Pulk. 55, 75. Oxfrd., Gmwch. 00, 64, Brsls., Giittingen, Paris 75. Yrnl., 

Rome, Krlsrhe. 

Paris 60, 75, Brsls., Oxfrd. 65, Glsgw., Gotha S5, A. N 

Pulk, 55, 71, 75, Lpzg., Trnl., Cambr., Rome, Gmwch. 80 

Pulk. 55, 75, Trnl., Osfrd. 60, 75, Paris 60, 75, Brsls., Grnwch. 64, 72, Rome. 
Pulk. 55, Grnwch. CO, 80, Paris 60, Brsls., Glsgw., Yrnl., Rome, A. G. 

Albny. 
Leidn., Rome, Pulk. 55, Trnl., Grnwch. 64, Oxfrd. 75, A. G 




Argelander 

Piazzi and others. 


Brad.2(con6rmed) 


Brad, and others. 




Brln.Jrhh -Yral.. Brsls., Rome, Fi. 11 .i ' , s;) 

Brln.Jrbl. .Paris 60, Brsls., Caiiilii 1:. li, di iiwch.80, 89 


Brad 13 




Piazzi and others. 
Groombridge and 
others. 


Pulk. 55, Oxfrd. 75, Grnwch. 72, 80, 88, Brsls., Paris TJ 


Berln, Jrbh., Oxfrd. 60, Ptiris 45, Pulk. 55, 75, Brsls., Trnl., Cambr., 

Rome, Grnwch. 80, 87, 88. 
Grnwch. 60, 80, Pulk. 55, Gottingen Crdba., Oxfrd. 75, Paris 75, Krlsrhe 

85, Gmwch. 80. 
Gmwch. 00, 72, 80, Pulk. 55, 75, Trnl., Brsls., Rome (Ri.therfurd's 

photographs). 
Pulk 55 Paris 75 Grnwch 80 


Brad.2(contirmed) 


Groombridge and 

others. 
Piazzi and others. 
Piazzi and otliers. 


Pulk 55 T5 Grnwch 60 80 Oxfrd 60 Brsls Glsgw Rome 


Pulk. 55, 75, Paris 60, 75, Bonn, Oxfrd. 60, Trnl., Glsgw., Brsls., Grnwch. 
80, 88, Gotha 85. 




Pulk. 55, 7.5, Oxfrd. 60, Gmwch. 64, 88, Brsls., Cambr.. Rome, Gotha Pr. 

Vertical. 
Berlin Jrbh., Yrnl., Brsls., Paris 75, Rome, Cambr. 75, Pnlk. 75, Grnwch. 

80, 87. 
Berlin Jrbh., Trnl., Brsls., Pans 60, Cambr., Rome, Pulk. 75, Gmwch. 

80, 89. 


Brad 5 


Brad.5 


Brad, and others.. 
Brad 8 




Brln. Jrbh., Oxfrd. 60, Trnl.. Paris 60, 75, 82, Cambr., Pulk. 75, Rome, 
Grnwch. 80, 88. 


Brad.4 


Berlin Jrbh., Paris 60, 82, Brsls., Trnl., Cambr., Berlin, Pulk. 75, Rome, 
Grnwch. 80, 87. 


Brad. 2 

Brad.8 


Pulk. 55, Grnwch. 64, 72, 80, Glsgw., Cambr., Rome 

Pnlk. 5!-,, Grnwch. 60, 80, Tml., Brsls., Pulk, 75 




Groombridge and 
others. 


Pulk. 55, Paris 60, Brsls., Glsgw., A.G.Cambr., Rome,Gotha, Pr. Vertical, 
Gmwch. 80. 


Brad 17 


Pulk 55 Paris 60 75 Rome Brln Gmwch 80 




Brln. Jrbh., Oxfrd. 60, Paris 60. 75, Trnl., Brsls. Washgtn. 68 (Boss), 
Glsgw., Cambr., Pulk. 75, Rome, Grnwch. 80, 87, 88, 88, 89. 

Brln. Jibh., Trnl., Brsls., Armagh, 75, Paris 75. Cambr., Pulk . 75, Rome, 
Grnwch. 80. 




Brad 3 











UNITED STATES AND MEXICAN BOUNDARY. 
Authorities for star catalogue— Coutinaud. 



53 



Ko. 

204 
205 
200 
207 

209 
209 
210 
211 
2:2 
213 
214 
215 
216 

217 
218 

220 

221 
222 
22a 
224 
225 
220 

227 
228 

229 

230 

231 

232 
233 

234 

230 
237 

238 
239 

240 
241 
242 
243 
244 
245 

240 
247 
248 

249 
250 


Authorities for 


Au thorites used for declinatiou in computing latitudes on the 
boundary. 


Observations added 
on revision. 


Arglndr.(A.N.)- 
Brad 5 


Pulk. 55, Brsls., Paris 00, 75, Glsgw., Eonie, Grnwch. 89 


Paris 45, 6U, 75. 

Paris 00, 75. 

Oxfrd 70. 
Greenwich 80. 

Greenwich 8S. 
Pulk 55. 


Pulk. 55, Grnwch. 60, 64, 72, 80, Paris 00, 75, Brsls., Glasgow, Rome 


Piazzi and otLers 
Brad. 23 


Brin. Jrbh., Pulk. 55, 75, lirsls., Ciimbr., Home, Brln., Gmwch. 80 

Pulk. 55, Grnwch. 00, 64, 72, Oxfrd. 60, Paris 60, 75, Brsls., Rome 


Brad. 2 and others 




Brad.2 


Pulk.65, Grnwch. 64, Brsls. Cape 80 Rome 




Pulk. 55, 75, Brsls., Rome, Berlin, A. G., Cambr., Paris 75, Grnwch. 80. . . 
Pulk.55, Grnwch. 64, 72, Amgh 75 Rome Brln 


Brad.8 


Brad.4 




Piazzi and others 
Brad 17 




Brln. Jrbh., Pulk. 55, 75, Brsls., Oxfrd., Paris 60, 75, Cambr., Rome 

Brln. Jrbh., Oxfrd. 00, Yrnl., Glsgw., Cambr., Pulk., Grnwch. 80. 88 

Washgtn. 08, Boss, Yrnl., Cambr., Pulk., Rome, Grnwch. 80, 88. (Brln. 

Jrbh. omitted.) 
Pulk. 55, Grnwch. 00 80 Brsls Rome Glst'w Cape 80 




Auwers.confrmd 

hy Boss. 
Brad. 5 






Brad 14 


Pulk. 55, Gmwch. 04, Brsls., Rome, A. G. Helsingfors, A. G. Cambr., 

Kazan, Pr. Vertical. 
Brln. Jrbh., Br.sls., Pulk.75, Grnwch. 80, Rome.Grnwch. 89, Auwerss303 

Stars. 


Brad 6 




Brad.2 


Pulk. 55 Grnwch 64 72 80 Paris 75 


Brad 10 


Brln. Jrbh., Yrnl., Cambr., Rome, Pnlk. 75, Grnwch. 80, 87 

Brln. Jrbh., Oxfrd. 60, Paris 60, 75, Brsls., Cambr., Rome, Pulk, 75 

Brin. Jrbh., Brsls., Paris 00, Cambr., Rome, Pulk. 75, Brln., Grnwch. 80 .. 
Brin. Jrbh., Pulk. 55. 75, Oxfrd. 60, Brsls., Yrnl., Glsgw., Cambr., Rome, 
Grnwch. 80, 89 




Brad 12 




Brad. 10 




Pulk, 55, 75, Gmwch. 60, 64, 72, 80, Oxfrd. 60, Paris 60, 75, Yrnl., Brsls., 

Gl.sgw., Rome. 
Pulk. 55, Paris 60, Grnwch. 60, 64, 72, 80, Brsls., Yrnl., Rome 

Pulk. 55, Trnl., Brsls., Rome, Grnwch. 80, Cinn 


Piazzi and later 

auths. 
Piazzi, Groom- 

bridge.andoth- 

Piazzi and later 
auths. 






Pulk. 5:. Oxfrd. 00, Grnwch. 04, Brsls., A. G. Leidn., Pulk. 75, Rome, 

Paris 75. 
Pulk. 55, A. G. Hl"frs Rome Brln Gmwch 87 


Brad. 18 


Brad.4 


Pulk. 55. Grnwch. 04, 72, 80, Oxfrd. 75 Rome Paris 75 


Brad.9 


Brln. Jrbh., Yrnl. Paris 60 Brsls Pulk 75 Rome Paris 75 




Brln. Jrbh., Tml., Oxfrd., Paris 60, Washgtu. 08, Boss. Glsgw., Paris 75, 

Cambr., Pulk. 75, Rome, Grnwch. 80. 

Brin. Jrbh., Pulk. 55, 75, Cambr., Rome, Grnwch. 80. 89 

Brin. Jrbh., Trnl., Oxfrd. 60, Bonn, A. N. Washgtn. 08, Boss, Glsgw., 

Cambr., Pulk. 75, Gmwch. 80, 88. 
Brln. Jrbh., Pulk.55, 75, Paris 00 Cambr Rome Grnwch 80 


Brad 18 




Brad.3 






Itadcliff and later. 
Brad. 15 


Pulk. 55, Ednbrc, Grnwch. 64, 72, 80, A. G. Christiania, Yrnl, Rome 

Paris 60, 75, Grnwch. 60, 04, 72, 80, 88, lirsls., PiUk, 75, Karisruhe, Cai)e. . . . 
Pulk. 55, A. G. Hlgfrs., Rome Brin Paris 75 Grnwch 80 


Brad.9 


Brad. 3 


Pulk. 55. 75, Paris 45, 60, 75, Brsls., Washgtn. 70, Grnwch. 72, Amagh. 75, 

Rome. 
Briu. Jrbh., Br.sls., Cambr., Pulk. 75, Brln., Rome. Grnwch. 80, 88 


Brad.3 

Brad. 2 and later.. 


Oxfrd. 75, Cinn., Brin. Jrbh., Yrnl., Paris, Cambr., Brsls., Rome, Pulk. 

75, Gmwch. 80. 
Pulk. 55, Grnwch. 60, 72, 80, Oxfrd. 00, Paris 00, 75, Brsls.. Trnl., Rome. . . . 
Brin. Jrbh., Oxfrd. 60, Paris 00, 75, Bonn 00, Brsls., Yml., Oxfrd. 75, 

Cambr., Rome. Pulk. 75, Grnwch. 80. 


Brad. 2 and later.. 
Brad. 15 





54 



UNITED STATES AND MEXICAN BOUNDARY. 

Authorities for star catalogue— Continued. 



Brad. 4... 
Brad. 12.. 

Brad. 4... 
Brad. 11.. 
Brad. 3... 
Brad. 5.. . 
Brad. 10.. 



Brad. 9 

Groombrid 



203 Brad. 5. . 
264 Brad. 3. . 
264 , Brad. 74. 



265 I Lalande and later 

266 j Brad. 71 

267 i Brad.4 

268 1 Brad.6 



Brad:4 

Brad.6 

Brad. 2 and later. 
Brad. 2 and later. 

Brad.3 

Brad.6 

Brad.4 



Groombridge and 

Brad.4 

Brad.5 

Brad.3 

Brad.3 

Brad.3 

Brad.3 

Brad. 2 (Cnfmid.) 

Brad.3 

Brad.3 

Lalande and later 

Brad.3 , 

Brad.5 

Lalande and later. 
Groombridge and 

later. 
Lalande and later. 

Brad.3 

Brad. 13 

Lalande and later 

Arglndr 

Brad.3 

Auwers's 



55, Gmwch. 64, Brsls., Trnl.. Glsgw., Oambr., Cape 80, Rome 

Jrbb., Pulk. 55, 75, Oxfrd. 60, Paris 60, Rome, Glsgw., Gruwcb. 80. . 
Jrbh., Yrnl., Paris 60, 75, Brussels, Glsgw., Cambr., Pulk. 75, Cape 
Eome, Gruwch.80,88. 

55, Gmwch. 64, Brsls., "Washgtn. 70, Rome 

, Grnwch. 72, 80, A. G. HeLsingfors, Rome 

, 55, Paris 60, Oxfrd. 60, Brsls., Grnwch. 64, Glsgw., Rome 

55, 75, Oxfrd. 60,Grnwch. 64, 80, Brsls., Cambr., Glsgw., Eome,Cinn 
, 55, Paris 60, Brsls., Trnl., Brln., Rome 

55, Paris 45, 60, Oxfrd. 60, Grnwch. 64, Eome, A. G., Cambr 

Jrbb., Pulk. 55, 75, Cambr., Berlin Grnwch. 80 

. 55, Ednbro., A. G. Helsingfors 



ngfors, Brussels, 



Pulk. 55, 75, Oxfrd. 60, Grnwch. 61, 72, 80, A. G 

Rome, Cinn. 

Pulk. 55, Paris 60, Grnwch. 64, Cambr., Cape 80, Rome 

Pulk. 55, Glsgw., Grnwch. 64, 72, 80, Paris 75, Brln., Rome 

Brln. Jrbh., Oxfrd. 60, Paris 60, 75, Trnl., Bonn 66, Washgtn. 68 Boss, 

Glsgw., Cambr., Puik. 75, Rome, Gmwch. 80, 88. 
Pulk. 55, Paris 60, 75, Grnwch. 80. 
Brln. Jrbh. , Oxfrd. 60, Brsls., Tml., Cambr., Rome, Pulk. 75, Grnwch. 80. 

Pulk. 55, Washtn. 70, A. G. Helsingfors, Brln., Rome, Grnwch. 80 

Brln. Jrbh., Pulk. 55, 75, Oxfrd. 60, Trnl., Brussels, Cambr., Rome, Paris 

75, Grnwch. 80. 

Pulk. 55, Gmwch. 80, 80, Paris 60, Oxfrd. 75, Rome 

Pulk. 55, Grnwch. 60, Brsls., Cambr., Paris 60, 75 

Pulk.55, Grnwch. 60, Brsls., Paris 60, Rome 

Pulk. 55, 75, Oxfrd. 60, Trnl., Grnwch. 64, 72, Brsls., Eome, Brln 

PiUk. 55, 75, Oxfrd. 60, Brsls, Gmwch. 64, 72, 80, Glsgw 

Pulk. 55, Grnwch. 60, 73, 80, 88, Paris 60, 75, Brsls., Rome 

Pulk. 55, Grnwch. 60, 72, 80, 88, Tml., Paris 75, Eomo 



Glasgo 
Glasgo 



Glsgw. 90. 
Grwch.90. 



Glsgw. 90not used. 



Pulk. 55, Gmwch. 64, Washgtn. 70, Brsls., Rome, Paris 75 

Brln. Jrbh., Pulk. 55, 75, Amgh.75, Paris 75, Rome, Cambr.,Greenwich 80 

Brln. Jrbh., Yrnl., Paris 60, 75, Glsgw., Rome, Pulk. 75, Cambr., Cape 80, 
Grnwch' 80. 

Pulk. 55, Trnl., Grnwch. 64,72, 80. Lpzg., Leidn.. Rome, Washgtn. Pr., 
Vrtcl. 

Pulk. 55, 75, Grnwcli. 60, 80, Paris 60, 75, Brsls., Rome ■. 

Pulk. 55, 75, Trnl., Grnwch. 60, 72, 80, Paris 45, 60, 75, Brussels, Rome. . . . 

Pulk. 55, Paris 60, Gmwch. 64, Glsgw., Rome, A. G. Albany 

Pulk. 55, Trnl., Paris 45, 60, 75, Washgtn. 70, Gmwch. 64, 72, Brus- 
sels, Rome, Glsgw. 

Paris 60, Pulk. 55, Brsls., Grnwch. 72, 80, A. G. Helsingfors, Rome 

Pulk.55,75, Paris 60, Grnwch. 64, 72, Brln 

Pulk. 55, Amgh. 75, Paris 75, Cambr., Grnwch. 87 

Pulk.55, Yrnl., Paris 75, Brln., Grnwch. 87 

Pulk. 55, Paris 45, 60, Trnl., Grnwch. 60, 64, 72, 80, 88, Rome 

Pulk.55, Paris 60, 75, Glsgw., Gmwch. 80 

Pulk. 55, Brsls., A. G. Hlgfrs., Eome, Greenwich, 80 

Trnl., Brsls., Paris 75. Cambr., Grnwch. 87 

Pulk 55, Paris 45, 60, 75, Grnwch. 04, 80, Washgtn. 70, Brsls., Glsgw 

Pulk. 55, Grnwch. 60, 64, 72, 80, 87, 88 

Pulk. 55, Giitt., Crdba., Paris 75, Krlsrhe., Grnwch. 80 

Brln. Jrbh., Pulk. 55, 75, Trnl., Rome, Grnwch. 80 

Pulk.55, Gmwch. 64, Glsgw., Pari875 

Pulk. 55, Brsls., Gottingen, Cape 80, Grnwch. 80, Krlsrhe 

Paris 45, 60, Pulk. 55, Grnwch. 60, 64, 72, 80, Trnl., Brsls., A. G. Chrstana., 

A. G., Hlgfrs., Rome. 

Pulk. ,55, Gmwch. CO, 64, 80, Yrnl., Rome., Paris 75 

Brln. Jrbh., Trnl., Paris 60, 75, Brsls., Rome, Pulk. 75, Cambr., Berlin, 

Paris. Grnwch. 80. 



Glsgw. 90. 
Grnwh. 90. 
Grnwh. 90. 



Glsgw. do. 



Greenwich 89. 

Greenwich 89, 60. 



Glasgow 90. 
Auwers's 303 Strs. 
Grnwh. 89, 90. 



UNITED STATES AND MEXICAN BOUNDARY. 

Authoritks for star catalogue — Continued. 



55 



No. 


Authorities for 
proper motion. 


Authorities used for declination in computing latitudes on the 
boundary. 


Observations added 
on revision. 


300 
301 
302 

303 
304 

307 

.308 
309 

310 
311 
312 
313 
3U 

315 
316 

317 

318 
310 

320 
321 
322 

323 

324 

326 

326 

327 

328 

330 

331 
332 

333 
334 

335 
336 
337 
338 

340 
341 


Brad 3 


Brln. Jrbh., Brsla., Glsgw., Rome, Pulk. 75, Grnwch. 80, 88 

Pulk.55,75, Grnwch. 60, 72, 80 88 Paris 45 60 75 Eome 


Grnwh.90. 
Gmwh, 89. 
Oxfrd. 64, Wash. 

75-6, Glsgw. 90. 
Grnwh.90. 
A.G. Camb.Kazan 

Pr. Vertical. 
Glasgow 90. 

Brln. 1888 A. N. 
No. 2912. 

Greenwich 90. 

Greenwich 87,89,90 
Greenwi.-b 90. 

Paris 60. 
Greenwich 89. 
Greenwich 90. 

Kazan Pr. Vertcal. 
Greenwich 89,90. 

Greenwich 90. 

Karlsruhe 87. 
Greenwich 89. 
Greenwich 89, 90. 

Greenwich 90. 

Cinn. Grnwh.90. | 
Gmwh. 89. 

Grnwh. 90. 


Brad. 5 


Piazza and others 

Piazza and others. 
Brad 19 


Pulk. 55, Paris 20, Grnwch. 64, A. G.Leidn.,Gl3gw 


Pulk. 55, 75, Trnl., Grnwch. GO, 80. Brsls., Cambr., Kome 

Pulk 55 Paris 60 Brsls Grnwcli 64 Glsgw Eome 


Brad 4 




Brln. Jrbh., Paris 60, 75, Xrul., Brsls., Eome, Pulk. 75, Cambr., 

Grnwch. 80. 
Pulk. 55, 75, Brsls., Paris 60, Waahgtn. 70, Brln., Eome, Greenwich. 80 

Brln. Jrbh., Pulk. 55. 75, Trnl., Brsls., Cambr., Eome, Grnwch. 80 

Pulk. 55. Gottingen, Brsls., Paris 75, Brln,, Crdba., Cape 80, Grnwch. 80, 

88, Krlsrhe. 

Brln. ,Trbh., Yrnl., Brsls., Pulk. 75, Cambr., Brln , Eome, Grnwch. 80 

PiUk. 55, Yrnl., Paris 60, 75, Brsls., Armgh., Grnwch. 80 

Pulk. 55, Paris 60, Brsls., Brln., Kome, Cambr., Grnwch. 80 

Pulk. 55, Grnwch. 60, 64, 72, Glsgw., Brsls., Cambr., Eome 

Pulk. 55, Grnwch. 60, 64, 80, Brsls., Yrnl., Glsgw., Amgh. 75, Eome, A. 

G., Albny. 

Brln. Jrbh., Yrnl., Paris 60, Eome, Pulk. 75, Cambr., Grnwch. 80, 88 

Pulk. 55, 75. Paris 45, Glsgw., Grnwch. 64, 72, 80, Brsls., Rome 

Brln. Jrbh., Pulk. 55, 75. Yrnl., Paris 00, 75, Glsgw., Cambr., Cape 80, 

Eome, Grnwch. 80, 87, 88. 

Pulk. 55, Grnwch. 64, -VYashtn. 70, Oxfrd. 70 

Grnwch. 60, 64, 72, Brals., Washgtn. 70, A. G. Hlgfrs., Rome 


Brad 3 


Brad 4 




Brad 3 


Lalande and later. 
Brad 3 




Brad 2 


Brad 27 


Brad.4 

Brad 4 




Groonibridge and 
later. 




Pulk. 55, Grnwch. 60, 80, Brsls., Glsgw., Eome 

Brln. Jrbh., Trnl.. Paris 60, 75, BrsU., Cambr., Glsgw., Pulk. 75, Grnwch. 

80, 88, Cape 80, Eome 80. 
Brln. Jrbli., Pulk. 55, 75, Brsls., Yrnl., Cambr., Eome, Grnwch. 80 

Pulk.55, A. G. Hb'frs Gruwch 80 




Piazzi, Groom- 
bridge, and later. 
Groombridge and 
later. 


Pulk. 55, Oxfrd. 60, 65, Grnwch. 60, 64. 80, Paris 60, 75, Yrnl., Brsls., 

Glsgw., Auwers's 303 Stars. 
Pulk. 55, Paris 60, Grnwch. 60, 64, 72, 80, Brsls., Yrnl., A. G. Chrstana., 

Eome. 
Pulk. 55, Paris 60, Grnwcb. 64, 72, Home 




Brad. 1 and latr. 

revisu. 
Piazzi and later... 

Brad 8 


Pnlk. 55, 75, Paris 60, 75, Yrnl., Brsls., Glsgw., Crdba., Grnwch. 80, Cape 

80,Krl8rbe.85. 
Brln. Jrbh., Yrnl., Brsls., Wasgtu. 70, Paris 6U, 75. Glsgw., Cambr., 

Eome, Pulk. 75, Grnwcb. 80, 88. 
Brln. Jrbh., Yrnl., Paris 60, 75, Glsgw., Cambr.. Cape 80, Pulk. 75, Eome, 

Grnwch, 80, 87. 
Brln. Jrbh., Yral., Paris 60, 75, Glsgw., Rome, Pulk. 75, Gruwch. 80, 87. . . . 
Pulk. 55, Yrnl., p'aris 75. Brsls., Grnwch. 80 

Pulk. 5.1. 75, Yrnl., Paris 60, 75, Grnwch. 64, Brsls., Oxfrd. 70, Kome 

Brln. Jrbh., Paris 60, 75, Yrnl., Brsls., Cambr., Glsgw., Pulk. 75, Eome, 
Grnwch. 80, 87, 88, Cape 80. 

Pulk. 55, Greenwich 64, 0.xfrd. 70, Glasgow, Kome 

Brln. Jrbh., Pulk. 55, 75, Oxfrd. 70, Cambr., Rome, Greenwich 80 

Pulk. 55, 75,Oxfrd. 60,Grnwch.60, 72, 80, Brsls., Yrnl., Rome, A, G. Albany 
Pulk. 55, 75, Oxfrd. 60, Grwnch. 60, 64, 72, 80, Brsls., Glsgw., Cambr., Eome 
Pulk. 55, Brsls, Gmwh. 80 

Berlin Jrbh., Pulk. 55, 75, Yrnl., Cambr., Glasgow, Eome 

Berlin Jrbh., Pulk. 53, Pr. Vrtcl. 69, 75, Washgtn. 70, Pr. Yrtcl.81, 90, 
Can.br., Eome. 


Brad. 12 

Brad 16 


Groombridge and 
later. 


Brad.7 

Brad.4 




Brad.5 


Groombridge and 

later. 
Brad. 2 (confrmd. 





56 



UNITED STATES AND MEXICAN BOUNDARY. 
Authorities for star catalogue — Continued. 



No. 


proper motion. 


Authorities used lor declination in computing latitudes on the 
boundary. 


Observations added 
on revision. 


342 

343 
344 
345 

346 

347 

348 
349 
350 
351 

352 

353 

354 
355 

356 
357 

358 
359 
360 

361 
362 

363 

364 

365 
366 
367 

368 

369 

370 
371 

372 
373 
374 

:!?5 

376 
377 
378 

379 
380 
381 
382 
383 
384 

385 


Piazzi and later... 


Pulls. 55, Brsls., Greenwich 64, 72, Oxfrd. 70, Armagh 75, A. G. Leiden, 
Cambr., Glsgw. 


Greenwich 90. 

Grnwch, 90. 

Greenwich 00. 

Karlsruhe, Glas 
gow flO. 

Grnwch. 89, 90. 
Greenwich 88, 89, 

Glsgw. 90. 
Cordoba 85. 

Cordoba, Grnwcli. 
90, Karlsruhe 89. 
Ciun. 

Crdba. 

Grnwcb. 89. 

Grnwch. 89, 90. 

Glasgow 90 
Brln. 85. 
Greenwich 90. 

Greenwich 89. 
Cinn. 
Greenwich 90. 






Brad 6 


Pulli. 55, Trul., Greenwich 60, 64, 80, 88, Brussels, Li-ideu, Leipzig.. 

Cambr., Auwers's 303 stars. 
Pulk 55 Yrnl Brussels Rome Grnwcli 80 


Groombridge and 

later. 
Groombridge and 

later. 
Brad.4 


Pulk 55 Paris 64 Cambr Rome Grnwcli 80 


Pulk. 55, Grnwcb. 64, 72, 80, Brsls., Oxfrd. 70, Cambr., Rome 




Pulk 55 A G Leidn Gmwch 80 


Brad. 1, cnfrmd. 
by Arglndr. 


Brln. Jrbh., Oxfrd. 60, Pulk. 55, 75, Trnl., Brussels, Cambr., Grnwcb. 80. . 

Pulk. 55, Grnwch. 60, 80, 88, Cambr., Rome, materials do not agree very 

well. 
Pulk. 55 Gruwch. 60, 64, 72 80, Yrnl., Cordoba Glsgw 


Brad 4 




Oxfrd. CO, Pulk. 55, Gmwch. 60,64,72,80, Yrnl., Brussels, A.G.Christiauia. 


Groombridge and 

later. 




Brad 8 


Brln. Jrbh., Pulk. 55, 75, Oxfrd. 60, Yrnl., Glsgw., Cambr., Greenwich SO, 

Auwers's 303 stars. 
Pulk 55 Grnwcb 64 80 Washgtn 70 Rome 


Brad 2 


Piazzi and later... 
Groombridge and 

later. 
Brad 7 




A G Chrstna Gmch 80 


Pulk. 55, Grnwch. 60, Brsls., Cambr., Rome, Gotha. Pr. Vrtcl. A. N 

Pulk. 55, Gmwch. 60, 64, 72, 88, Yrnl., Glsgw., Karlsruhe 

Puik.55,75,Oxfrd.60, Bonn, Brsls., Grnwch. 72,80, A. G. Helsingfurs, 

Rome. 
Brln. Jrbh., Yrnl., Pulk. 55, 75, Cambr., Rome, Grnwch. 80 

Oxfrd. 60, Brsls., Gott., Glsgw., Krlsrhe., Gotha A.N 




Piazzi, Groom- 
bridge, etc. 

Piazzi, Groom- 
bridge, etc. 

Piazzi, etc 


D'Agelet, La- 

lande, etc. 
Piazzi, Grmbdg., 

etc. 
Arglndr 


Ednbro., Brussels, Washgtn. 70, Oxfrd. 70, Armagh 75, Paris 83, Gruwch. 

87. 
Brln. Jrbh., Pulk. 55, 75. Yrnl., Bonn, Cambr., Rome, Grnwch. 80, 

Washgtn., Pr. Vrtcl. A. J. 

Brln. Jrbh., Pulk. 55, 75, Cambr., Rome, Grnwch. 87, 88 

Pulk. 55, 75, Brsls., Grnwch. 60, 64, 72, 80, Washgtn. 70, Glsgw., Paris 82. . 
Pulk. 55, Grnwch. CO, 64, Yrnl., Brussels, Cambr., Gmwch. 72,80,87,88, 

Auwers's 303 stars. 
Pulk. 55, Grnwch. 87, Brln. 88 






Grmbrdg., etc.... 

Grmbrdg., etc 

Brad. 33 

Brad. 2. cnlrmd. 

by Arglr. 
Piazzi. etc 


Brln. Jrbh., Yrnl., Oxfrd. 60, Glsgw., Cambr., Pulk. 75, Rome, Gruwch. 

80, Gotha, Pr. Vrtcl. A. N. 
Pulk 55 75 Grnwch 64 Yrnl Bonn Brsls Rome Gls"w 


Pulk 55 Engsbrg 60 Brsls Grnwch 80 




D'Agelet, Piazzi, 
etc. 

Grmbrdg., etc 

No very old data.. 
Arglndr 


Glsgw Crdba Krlsrhe 


A G Chrstana Gmwch 88 




A G Hlgfrs Pulk 75 Gmwch 87 


Piazzi, etc 

Brad.3 

Brad. 1, cnfrmd.. 

Boss. 
Brad 4 




Pulk 55 Oxfrd 60 Gruwch 64 T> 80 Brsls Gl8"w Rome 


Brln. Jrbh., Brsls., Pulk. 75, Cambr., Rome. Gmwch. 80, 87 







UNITED STATES AND MEXICAN BOUNDARY. 
Authorities for star catalogue— Cout'mned. 



57 



Authorities for Authorities used for declination in couiputiDK latitude 

proper motion. boundary. '' 



Brad. 4. 



Grmbrdg., etc 
Lalande, etc . 

Brad.2 , 

Lalande and others 
Grmbrdg. a 

others. 
Brad.2 



Brad.2 

Arglndr. revised . 
Arglndr. revised. 

Piazzi and others 

Brad.2 

Groombridge and 

others. 

Brad.2 

Groombridge and 

others. 
Piazzi and others 

Brad.3 

Brad.3 

Brad.2 



Pulk. 55, 75, Brsla., Gmwch. 64, 72, 80, 8«, Washgtn. 70, Glegw., Rome. 

Palk.55, 7.5,Glsgw.,A.G. Albny., Gmwch.87 

Brln. Jrbh., Trnl., Cambr., Glsgw., Pnlk. 75, Eome, Grnwch. 80. 87 . . , 

Brln. .Jrbli. crctd. for precsu., Pulk. 55. 75, Carabr., Eome, Grn-n-ch. 80 

Glsgw., Kr.sls., A. G. Leidn., Rome, Amgh. 75, Brln. 88 

Brln. Jrbh., Pulk. 55, 75, Brsls., Cambr., Brln., Eome 

Amgh. 75, Cambr., Pulk 75, Gmwch. 80 

Eome, Grnwch. 80 



Pnlk. 55, Yrnl., Grnwch. 60, 64, 72, 80, Eome 

Pulk. 55, 75, Grnwch. 80 

Pulk. 55, 75, Brsls., Brln., Eome, Grnwch. 80 

Pulk. 55, 75, Tml., Brsls., Grnwch. 64, 72, 80, Eome, Cinn 

erctd., Pulk. 55, 75, Oxfrd. 60, Brsls., Cambr., Eome, Grnwch. 



Brln.Jr 



Pulk. 55, Grnwch. 64, 72, 80, Brsls , Glsgw., Eome 

Palk. 55, Gmwch. 60, 80, 88, Glsgw., A. G. Albny., Eome 

Bonn, Pulk. 55, 75, Brsls., Cambr., A. G. Hlgfrs., Eome, Grnwch. 



Pulk. 55, Grnwch. 60, 72, 80, Brsls., Eome. 
Washgtn. 70, Eome, Grnwch. 88 



Groombridge and 

Brad.2 

Piazzi, Groom- 
bridge and oth- 

Brad. 1 and later.. 



Piazzi, Gi 
bridge an 



Brad. 2 and others 



Brad.2 

Ednbro. 44 oldest 
authority. 

Brad. 2 

Piazzi and others . 
Bratl.6 



Pulk. 55, Trnl., Grnwch. 60, 80, Brsls., Rome 

Pulk. 55, 75, Trnl., Gmwch. 64, 72, 80, 88, Brsls., A. G. Leidn., Eome 
Pnlk. 55, 75, Yrnl., Grnwch. 64, 72, 80, A. G. Leidn., Rome, Glsgw. . . 

Brln. Jrbh., Pulk. 65, 75, Tml., Brsls., Glsgw., Eome 

Pulk. 55, Brsls., Ednbro., A. G. Hlgfrs., Cambr., Eome, Grnwch. 80. 
Glsgw., Rome 



Grnch. 90. 
Cinn.,Gls! 



Glsgw.-90. 
Greenwich 90. 



Pulk. 55, Grnwch., Yrnl., Gtngn., Brals., Glsgw 

Pulk. 55, Brsls., Grnwch. 72, 80, 88. A. G. Hlgfrs., Cambr., Eome. Brln. 88. 



Pulk.55,Grnwch.64, 87, Oxfrd. 75. Paris 83 

Pulk. 55, Brsls., Brln., Home, Grnwch, SO 

Pulk. 55, Brsls., Washgtn. 70, Amgh. 75. Rome, Grnwch. SO . 

Pulk.55, Grnwch. 60, 80, 88, Brsls., Rome 



Brad. 1 and Liter.. 
Arglndr (revised) 



Brad. 7. 
Brad. 1 . 
Brad. 3. 



Brad. 4 

427 I Piazzi and later.. 

428 j Brad.2 

429 Brad.3 

430 Brad.6 

431 ! Brad.lO 

432 I Lalande and oth- 



Pulk. .M, 75, Grnwch. 60, 64, 72, 80, Brsls., Yrnl., Rnmi- 

Pulk. 5-% Brsls., A. G. Hlgfrs., Eome, Grnwch. 80 Kazan Prime i 

I tjcal. 

Pulk. 55, 75, Trnl., Grnwch. 60, 72, 80, 88, Oxfrd. 60, BrsLs., Eome I Grnch. 90, Cinn 

Pulk. 55, Yrnl., Brsls., GLsgw., Grnwch. 72. 80, Amgh. 75, Eome j 

Brlu., Jrbh., Oxfrd. 60, Brsls., Glsgw., Yral., Cambr., Pulk. 75, Cape 80, i Grnch. 89. 9(1. 
Eome. Grnwch. 80, 88. i 

Pulk. .55. 75, Yrnl., Brsls , Brln., Eome, Grnwch. 80 1 

Brln. Jrbh.. Pulk. 55, 75, Washtn. 70, Brsls., Cambr., Rome. Grn\ 



Kazan Prin 
tical. 



, 88, Washgtn. 70, Cambr 



Pulk. .55, 75, Grnwch. 60, 80, Brsls., Rome . . . 
Pulk. 5.5, Brsls., Grnwc-h. 64, Glsgw., Rome . 
Pnlk. 55, 75, Yrnl., Oxfrd.60, Grnwch. 64, 72, 1 

Glsgw., Rome. 
Brln. Jrbh., Oxfrd. 60, Brsls., Cambr., Pulk. 75. Rome. Grnwch. 88 . 

Pulk. 55, 75, Brsls., Yrnl., Green. 72, 80, Rome 

Pnlk.55, Grnwch. 64, Brsls., Oxfrd. 70, 75, Glsgw 

Pulk. 55, Grnwch. 60, 80, Brsls., A. G. Albny., Rome , 

Brln. Jrbh., Yrnl., Oxfrd. 60, Cambr., Eome, Pulk. 75, Grnwch. 80, 8 

Brln. Jrbh.. Yml., Cambr., Pulk. 75, Eome, Gmwch. 80, 87 

Pulk. 55, Amgli. 75, Crdba., Grnwch. 80 



Greenwich 89, ! 
Greenwich 90. 
Greenwich 89, i 



S. Doc. 247 8 



58 



UNITED STATES AND MEXICAN BOUNDARY. 
Authorities for star catalogue — Continued. 



No. 


proper motion. 


Authorities used for declination in computing latitudes on the 
boundary. 


Observations added 
on revision. 


433 






Berlin 85, Green, 
wich 90. 






434 

435 
430 


DAgelet, Strove. 










Bra.1.2 


Pulli. 55, 75,Tml., Brsls., Grnwch. 60. 72, 80, Paris 64, A.G. Leidn., 








Eome. 




437 




Brln. Jrbh., Oxfrd. 60, Brsls., Trnl., Glsgw., Cambr., Rome, Pulk.75. 
Grnwch. 80, 87, 88. 


Greenwich 89, 90. 




438 




Pulk. 55, Amgh. 75, Cambr., Grnwch. 80, Ann Arbr., Wasbgtn. 82 


Glasgow 90. 


439 


Groombridge .and 
others. 


Brln. Jrbh. crctd., Pulk. 55, Yrul.. Cambr., Kome, Grnwch. 80 








Brln Jrbh Trnl Oxfid 00 Brsls Washo-tn.70 Eome, Pulk.75 . 


Greenwich 89. 














Rome, Grnwch. 80, Washington, Prime Vertical. 




442 
443 








Piazzi and otLers. 
Kadcliff and others 




Washington 81. 
Greenwich 89,90. 


Grnwch. fiO, 64, 72, 80, 88, Pulk. 55, Ednbro., Brsls., Eome, A. G. Hel- 






singfors. 




445 


Piazzi and others. 


Pulk. 55, Brsls., Glsgw., Yrnl.. Eome, A. G. Albny., Grnwch. 80 




440 


Groombridge and 
others. 


Pulk. 53, Grnwch. 60, 64, Washgtn. 70, Glasgow, Rome 


Glasgow 90. 














Pulk. 55, Trnl., Grnwch. 64, 87, 88, Brsls., Glsgw., Amgh. 75, Rome 
















Greenwich 89, 90. 






Grnwch. 80, 88, Eome. 
















303 .Stars. 










Grnch 90 














Pulk. 55, 75, Oxfrd. 60, Brsls., Washington 70, A. G. Cambr.. Rome, Paris 
82, Gotha 85, A.N. Grnwch. 80. 












Groombridge and 
others. 




Greenwich 90 








456 


Groombridge jiud 
others. 


Pulk. 55, Grnwcli. 60, 80, Oxfrd. 60, Brussels, Rome 










458 


Brad.l 


Pulk. 55, Yrnl., Washgtn. 70, Brsls., Grnwch. 72, 80, Rome, Paris 83 








Brln. Jrbli., Osfnl. 60, Brussels, Cambr., Glasgow, Pulk. 75, Eome, Green 


Grnch. 89,Glassow 






wich80.C.ape84. 


90. 






Berlin 84 




Brad 8 


Brln Jrbh Pulk 55, 75 Cambr. Eome, Ginwcb. 80 


Grncli.89. 


462 


Brad. 12 


Pulk. 55, 75. Oxfrd. 60, Brsls., Yrnl., Grnwch. 04, 80, Cambr., Glsgw., 
Crdba., Cape 84. 


Cinn. 




Groombridge and 
otlit-rs. 




(Jreeunich 89 


-ini 


Pulk. 55, Cape 60, Grnwch. 64, Brsls., Glsgw., Eome, A. G. Albany 




465 


Groombridge and 
others. 










Groombridge and 
others. 


















Glasgow 90. 






































only for proper niodon.) 






Brln. J. bh., Yrnl., Oxird. 60, Cape 60, 80, Glsgw., Can.hr., Pulk. 75. Rome, 
Grnwch. 80. 








Glsgw. 90. 


473 


Brad.5.... 


Pulk.55, Yrul.,Glsgw..Brln., EomcGrnwcb.SO 




474 


Brad.S9 


Pulk. 5,1, 75, Yrnl., Grnwch. 00, 72, Leidn., Lpzg., A. G. Hlgfrs., Eome, 






Cambr. 





U.MTED STATES AND MEXICAN BOUNDARY. 

Authorities for star catalogue— Cimt'manA. 



59 



No. 


Authorities for 
proper motion. 


Authorities used for declination in computing latitudes on the 
boundary. 


Observations added 
on revision. 


475 
476 

477 

478 
479 
480 
481 
482 

483 
484 






Glsgw. 90, Green- 
Greenwich 89, 90. 
Greenwich 89, 90. 

Grnch.90. 
Grnch. 90. 
Grnch.89,90. 
Grnch. 90. 
Vienna (Ottakriug). 

Grach.89,90. 
Washington 79, 85. 
Grnch. 90. 

Greenwich 89, 90, 
Glsgw. 90. 

Greenwich 90, 
Glsgw, 90. 

Cinn. 

Grnch. 90. 
Greenwich 89, 90. 

Grnch. 89, 90. 
Glsgw. 90. 

Grnch.89. 


Groombridge and 

others. 


Gmwch. 64, 87, Glsgw., Rome 




Brad. 13 


Grnwcli. 60, 64, 72, 80, Talk. 55. 75, Brsls., Yrnl., Canibr Rome 


Pulli. 55, Gruwch. 64, Brsls , Glsgw 






Brad. 4 


Tulli. 55, Trul.,Br8l8.,Gls<'w., Gmwch 80 Auwers's 303 Stars 


Groombridge and 
later. 

Piazi-.i, Groom- 
bridge, an<l oth- 

Brad.48 

Brad 7 




Pulli. 65, Osfrd. 60, Grnwch. 72, 80, Lpzg., I.eidn., Brussels, Cambr., 
Rome, Ann Arbr., Washgtn. 83, Kaneuburg. 

Brln. Jrbh., Pulk. 55,75, Oxfrd., Yrnl., Brsls.. Cambr., Glsgw., Rome, 
Gotha 80, Prime Vertical, Gmwch. 80. 

Pulk.55,Trnl., Grnwch., 72, 80, Glsgw., Rome 

Pulk. 55, 75, Tml.,Br3l.s., Glsgw.. Brln,, Rome, Grnwch. 80 


486 


Brad. 4 . 










Brln. Jrbh., Yrnl., Cambr., Rome, Pulk. 75, GUgw., Grnwch, 80 

Pulk. 55, 75, Oxfrd. 60, Grnwch. 64, Brsls., Glsgw., Rome, Cinn 

Pulk. 55, Grnwch. 60, 80, Rome, Cambr, Paris 83 












LalandeandotUer-s 




Pulk. 55, Yrnl., Grnwch. 64, 80, Glsgw., Rome, Washgtn., Prime Vertical 

A.J. 
Pulk. 55, 75, 90 (Pr. Vrtil.), A, N. Rome, A. G. Helsingfors, Grnwch. 80. . . 

Pulk, 55, Amgli. 75, A. G. Leiden, Cambr., Ann Arbr., Grnwch. 80 

Yrnl , Grnwch. 60, Brsls,, Pulk. 55, Home, Grnwch. 80 


493 


Piazzi, Groom- 
bridge, and oth- 


495 


Brad.2 










Pulk. 66, Yrnl,, Gruwch. 64, Washgtn. 68 (Boss), Cambr., Rome, Glasgow 
Pulk. 65, A. G. Leidn.. Amgh. 75, Cambr., Ann Arbr., Grnwch. 80 










500 

501 
502 

50;i 
504 

606 
506 
507 


later. 
Groombridge and 

later. 
Brad 3 




I'ulk. 55, Yrnl., Grnwcli. 60, 72, 80, 87, 0.\lrd. 60, Brussels, Rome 

Brln. Jrbh., Brsls., Yrnl., Glagw., Cambr., Pulk. 75, Greenwich 80, 88, 

Auwers's 303 Stars. 
Pulk, 55, Grnwch. 64, 72, Cambr., Rome, Glsgw 




lirad.3 

Brad. 3 




Pulk, 55, Grnwch, 60, 80, Bonn, Ednbro., Amgh. 75, Brsls., Glsgw., Rome. 


Tirn.l on 


I'ulk. 53, Grnwch 60 Lpzg Leidn Grnwch 72 Rome 






509 


Groombridge and 

others. 
Brad 4 


Oxfrd. 00, Pulk. 55, 75, Bonu, Grnwch. 64, 72, 80, Brsla., A. G. Chrstana., 
Gruwch. 80, Rome. 

Pulk. 55, Yrnl., A. G. Helsingfors, Brln., Grnwch. 80 

Brlu. Jrbh., Oxfrd. 60, Brsls., Y^rnl., Cambr., Pulk. 75, Rome, ( Irnwch. 80, 

Pulk 55 Brsls Grnwch 80 


511 


Brad. 24 


513 

514 
515 

516 
517 
618 


Brad.5 








Brln. Jrbh., Brsls., Cambr., Rome, Pulk. 75, Gmwch. 80, 88 

Pulk. 55, 73, Yrul., Grnwch. 60, 80, Brsls.. Rome, Glasgow 

Pulk. 55, Grnwch. 60, 80, Oxfrd. 60, Brsls., Yrnl., Glsgw., Cambr., Rome. . . 
Brln. Jrbh, Oxfrd. 60, Brsls., Yrnl., Cambr., Pulk. 75, Brlu., Grnwch. 80, 
88, Rome. 


Brad. 22 










' 





60 



UNITED STATES AND MEXICAN BOUNDARY. 
Authorities for star vataloyue — C'outinueil. 





No. 


Authorities for 
proper motion. 


Authorities used for declination in cnmpnting latitudes on the 
boundary. 


Observations added 
on revision. 




520 

521 
622 

524 
525 
526 
527 
528 
629 

530 

531 
532 

533 
534 

535 
536 
537 
538 

539 

510 
541 

642 

543 

544 

545 
646 

547 
548 
549 
550 
551 

552 
653 

554 
555 

556 

557 

558 
.559 
560 

561 

562 


Brad. 2 and later.. 
Brad 23 


Pulk. 55, Oxfrd. 60, Grnwcli. 64, Gottiugeu, Brussels, Yrnl., Glsgw., 

Eome.Krlsrhe. 
Pulk 55 Oxfrd Grnwch. 64, 72, Lpzg., Leidn.. Rome 


Grnch.89. 

Greenwich 90. 

Greenwich 89, 90, 
Glsgw. 90. 

Glsgw. 90. 

Gmch.89,go. 
Grnch.89,Cinn. 
Glsgw. 90. 
Glsgw. 90. 

Grnch. 89. 90. 

Greenwich 89. 
Greenwich 89. 

Greenwich 90, 
Washington 75. 

Karlsruhe, Ulsgw. 
90. 

Glasgow 90. 
Greenwich 89. 

Grnch. 89. 
Grnch. 90. 
Glsgw. 90. 
Greenwich 89, 90, 
Glsgw. 90. 

Greenwich 89, 90. 
Kazan Prime Ver- 
tical. 




Fiazziand later... 
Brad 3 






Brln. Jrbh., Oxfrd. 60, Yrnl., Brsls., Cambr., Pulk. 75, Glsgw., Rome 








Brad 6 


Brln.Jrbh.,Pulk.55, 75, Yml.,Brsls., Glsgw., Rome 

Pulk. 55, Yrnl., Brsls., Glsgw., Grnwch. 72, 80, Rome 

Pulk. 55, Grnwch. 64, 72, 80, 88, Brsls., Glsgw., Rome 

Pulk. 55, 0.xlrd. 60, Grnwch. 60, 64, 72, 80, Tml., Ednbro., Brsls 

Rome, Cambr., Gotha Pr. Vrtcl. A. N., Grnwch 

Pulk. 55, 7.5, Oxfrd. 60, Brsls., Grnwch. 64, 80, Glsgw., Rome, A. G. Albn.v . 

Pulk. 55, Grnwch. 80, Cambr., Ann Arbr 

Pulk. 55 (62 Pr. Vrtcl ), 75,81 (Prime Vertical), 91 Pr. Vrtcl., Brussels, 

A.G. Hlgfrs., Grnwch. 72, Brln. 
Pulk. 55, Grnwch. 64, Glsgw, Yrnl., Rome 








Brad 3 




Brad. 1 and latei.. 
Groombridge and 

later. 
Brad 4 








Brad, land later.. 




Groombridge and 
later. 










Pulk. 55, Oxfrd. 60, Grnwch. 60, 64, Brussels, Yrnl., Cambr., Glsgw., Rome 

Pulk. 55, Oxfrd. 60, Glsgw., Brsls., Yml., Grnwch. 72, Brln 

Pulk. 65, Brsls., Washgtn. 70, Glsgw., Lpzg., Leidn., Grnwch. 72, A. G. 

Cambr., Rome. 
Brln. Jrbh., Yml., Glsgw., Brsls., Polk. 75, Rome, A. (i.AIbany, Grnwch. 

80, Auwers's 303 Stars. 
Palk 65 Washington Grnwch 60 72 80 Rome Cambr 




Brad 6 




Piazzi and later.. 








Piazzi, Groom- 
bridge, and 
others. 






Ednbro., Brsls., Glsgw., Grnwch. 72, 80, Yarnall, Rome 

Pulk. 55, 75, Yrnl., Ednbro., Grnwch. 72, A. G. Helingfors, Rome 

Brln. Jrbh., Pulk. 55, 75, Oxfrd. 60, Glsgw., Brsls., Yrnl., Rome, 
Grnwch. 80. 




Brad. 12 (Sector 

obsrvns.). 
Brad.2(cnlriBd.) . 

Piazzi and later... 








Brad 9 


Pulk. 55, Grawcb. 60, 64, 72, 80, A. G. Chrstana., Rome 

Pulk. 55, 75, Bonn, (ilsgw., Armagh 75, Cambr., Ann Arl>r., Grnwch. 80 . . 










Yrnl Ednbro., Oxfrd. 65, Brsls., Amgh 75 Grnwch 80 




Groombridge and 

later. 
Brad 5 






Grnwch. 60, 72, 80, Pulk. 55, 75, Yrnl., A. G. Hlgfrs., Rome 

Pulk 55 75 Grnwch. 60, 64,72,80, Yml., Glsgw , Rome 
















Brln. Jrbh., Yrnl., Oxfrd. 60, Glsgw., Cambr., Pulk. 75, Rome, Grnwch. 

80,88. 
Pulk. 55, Yrnl., Ednbro., Rome, Brln., Gmwch. 80, Palmero (reduced 

from 6 Pr. Vrtcl. obsrvns.). 
Oxfrd. (rejected hut retained on revision), Brsls., Grnwch. 64, Pulk., 5.S, 

Yrnl., Glsgw. 
Pulk 55 Yml Grnwch. 64, Brsls Rome Glsgw., A. G. Albny 












Brad 3 












Pulk.55, Yrnl., A.G. HI gfs., Grnwch. 72 




Groombridge and 

later. 
Groombridge and 

later. 




A.G. Chrstana., Grnwcli. 80 



UNITED STATES AND MEXICAN BOUNDARY. 

AnihoritUs for star catalogue — Coutiuueil. 



61 



Brad. 5.. 
Brad. 3.. 
Brad. 4. 



Pnlt. 55, GIsgw., Grnwch. 64, Gtngn., Rome, Krlsrh . 

Palk. 55, Amgh. 75, Grnwch. 64, Glsgw., Rome 

Palk. 55, 75. Gmwih. 60, 64, Tnil., Cambr., Krlsrh . . . 



Piazzi, G; 
bridge 

568 Brad. 7.... 



Oxfrd. 60, lionii, Piilk. 5.^., Cruwch. 64, lllngn 

Krlsrl.e. 
Grnwch. 60, 72, 80, ( )xrrd. 60, Pulk. .=■,->, Brsl.s., R« 



.. Glsgw., Crdba., 
G. Hlgfra 



ireenwich 89, 90, 
Glasgow 90. 



Brad. 3 , 

Brad.4 

Brad. 2 and later. 

Brad.7 

Piazzi and later.. 
Groombridge and 

later. 
Brad.4 



Brad.4 

Brad. 2 and later 
Brad. 10 



id. 2 



,nd 



Arglndr. 

Brad.3 

Groombridgo anil 

others. 

Brad.5 

Br.id.4 

Groombridge and 

others. 
Groombridge and 

others. 
Piazzi and others 

Brad.4 

Groombridge and 

others. 
Groombridge and 

others. 
Brad.8 

Brad. 6 

Groombridge and 
others. 

Brad.9 , 

Groombridge and 

others. 
Brad. 1 and others 

Brad. 10 , 

Brad. 11 



Grnwch. 60, 64. 72, 80. Oxfrd. 60, 70, Pnlk. 55. Brussels. Trnl.. Rome, A. G. 
Helingfors. 

Pulk. 55, Trnl., Glsgw., Grnwch. 64, 72, 80, Rome 

Brln.Jrbh., Pulk. 55, 75, Cambr., Rome 

Pulk. 55, Grnwch. 64, 80, Glsgw.. Rome 

Brln. Jrbh., Yrnl., Cambr., Rome, Pulk. 75, Grnwch. 80 

Yml., Pulk. 55, Oxfrd. 60, Brsls., Glsgw., Grnwch. 80 

Glsgw., Rome, Pulk. 75, Grnwch. 80 



Greenwich 89, 90. 



Pulk. 55, 75, Grnwch. 60, 80, Brsls., Trnl., Glsgw., A. G. Albiiy., Rome .. . 
Brln.Jrbh., Oxfrd. 60, Trnl., Brsls., Glsgw., Cambr., Pulk. 75, Grnwch. 

80, Auwers'a303 Stars. 
Pulk. 55, 73, Oxfrd. 60, Brsls., Yrnl,, Grnwch. 72, SO. (Nos. 3744 aiul 3745 



I the s 



Grnwch. 60, 72, Pulk. 55, Brsls, Tril., A. G.Hlgrs 

Pulk. 55, Glsgw., Grnwch. 64, Rome 

Brln. Jrbh.. Oxfrd. 60, Trnl , Glsgw., Cambr., Pulk. 75, Grnwch. 80, 88 . 



Pulk. S.'i, Grnwch. 64, 72, 80, Brsls., Rome 

Brln. Jrbh,. Yrul., Pulk. 55, 75, Cambr., Rome, (ireenwich 80 , 



Glsgv 

Green 

Glasg 



Pulk. 55, Grnwch. 60, 64, 72, 80, Oxfrd. 60, Brsls., Rome. 
Pnlk. 55, 75, Glsgw., Rome, Grnwch. 80 



Brln.Jrbh.,Br8ls., Trnl,, Cambr., Rome, Pulk. 75, Grnwch. 80, 88, Glsgw. 
Brln. Jrbh., Oxfrd. 60, Glsgw., Brsls., Trnl., Cambr., Itome, Pulk. 75, 



Brsls., A. G. Chrstana., Grnwch. 72, 80, Rome 
Pulk. 55, Brsls., Grnwch. 72, 80, Rome 



Pulk. 55. Trnl., Brsls., Glsgw., Grnwch. 72. 80, Crdba., Krlsrhe. 85. . . 

Pulk. 55, Glsgw., Grnwch. 64, Trnl., A uwers' 303 Stars 

Pnlk. 55, Bonn, Brsls., Lpzg., Leidn., Glsgw., Grnwch. 72, 80, Rome . 



Pulk. 55, 75, 91 Pr. Vrtcl., Rome, A. G. Hlgfrs 

Pulk. 55, 75, Oxfrd. 60, Grnwch. 60, 64, 80, Brsls., Trnl,, A. G. Alban 

Brln. Jrbh., Trnl., Oxfrd., Glsgw.. Cambr,, Pulk. 75, Rome, (ireenwii 

80,88. 
Brsls., Grnwch. 64, 72, A. G. Chrstana 



Pulk. 55, Grnwch, 60, 72, 80, Glsgw., Yrnl., Brsls,, Crdba., Krlsrhe, i 

rejected (1 obsrvn). 
Brln. Jrbh., Oxfrd. 60, Trnl., Glsgw., Cambr., Pulk. 7.^., Rome, A. 

Albny., Grnwch. 80, Auwers's 303 Stars. 
Pulk. 55, 75, AG. Hlgfrs 



Trnl., Pulk. 55, 75, A. G. Hlgfrs., Brln., Rome, Grnwch. 80 

Brln. Jrbh., Pulk. 53, 75, Trnl., Cambr., Rome, Grnwch. 80 

Brln. Jrbh., Pulk. 55. 75, Oxfrd. 60, Trnl., Glsgw., Rome, Grnwch. 80, 
303 Stars. 



Greenwich 89, 90, 

Glsgw. 90. 
Karlsruhe 89. 
Glsgw. 90. 



Pulk. 62, Prime Ver 



Karlsruhe 88. 

Greenwich 89, 90, 
Glsgw. 90. 

Pnlk.62, Prune Ver- 
tical, Grnch. 89. 

Greenwich 90. 
Pulk.85,Greenwich 
89, 90, Glasgow 90. 



62 



UNITED STATES AND MEXICAN BOUNDARY. 
Authoriiics for star catalogue — Continued. 



No. 


Authorities for 


Authorities used for declination in computing latitudes on the 
boundary. 


Observations added 
on revision. 


602 
603 

604 

605 
606 
607 
608 

609 

610 

611 
612 

613 
6U 
615 

616 
617 

618 

619 

620 
621 




Pullt.55,75,Grnw<!li.6n,64.Trnl.,Brsls., Canilir.,Ronie 

I'lilk. 55, 75, Gruwch. 60, 64, Brsls., Glsgw., A. G. Hlgfrs, Rome 

r.jlk. 55, 75, Trnl., Oxfrd. 60, Grnwch. 64, 72, 80, GIsgw., Brsls., Rome, Pr. 
Vrtcl.Wshgtn. 


Washington 76, 84, 
Grnch. 89, Glas- 
gow 90. 

Greenwich 89. 

Greenwich 89. 
Glasgow 90. 


Piazzi, Grooin- 
bridge,andotli- 

Brad.5 


... 




R 






Brln.Jrbh.,Trnl., O^lfrd. 60, Cambr., Glsgw . Pulk. 75, Rome. Alhiiy., 

Grnwch. 80, Anwers's 303 Stars. 
Pulk. 55, Oxfrd. 60, Grnwch. 60, 64, 72, 80, Yrul., Brsls., Glsgw.. A. G. 

Albny., Rome. 
Pulk. 55, Grnwch. 60, 64, 80, Oxfrd. 61), Brsls., Tml., Glsgw., Rome, A. G. 

Albny. 




■Glsgw. 90. 




89, Glsgw. 90. 


Braa.6 

Brad, land others 


Glasgow 90. 


Pulk. 55, 62(Pr.VrtcI.)7."i,91Pr.Trtcl., Yrnl., Ednhro., Brsls., A. G. 

Hlgfrs., Grnwch. 72, lirln. 
Pulk. 55, Grnwch. 60, 64, 80, Oxfrd. 60. Glsgw., Yrnl., A. G. Albny., Rome 




Auwers's Brad, 
least squares. 




Greenwich 88. 

Kazan Prime Ver- 
tical. 

Kazan Prime Ver- 
tical. 


Yrnl., Brsls.. Glsgw., Pulk. 75 

Pulk. 55, A. G. Hlgfrs., Brln., Glsgw., Cambr., Rome, A. G. Cambr., 

Grnwch. 80. 
Pulk. 55, Yrnl., A. G. Hlgfrs., Rome, Brln.. A. G. Cambr., Grnwch. 80 ... . 


Brad. 2 and others 

Bra-'. 6 

Groombridge and 
others. 




Piazzi and others 







ASTRONOMY. 



HaYFORD, As.SIST.4NT A.STIiOXUMKU. 



San Diego, Ual., December 23, 1S9X 
The work of the astrouomical party began at Washington, D. C, in December, 1891. The 
instruments were there prejiared for u.se and their principal constants determined. The early 
part of February, 1893, was spent at El Paso in making the tinal preparations for the field. 

On February 12, 1892, the party went into camp near El Paso, in conjunction with the other 
survey parties, fully equipped and prepared for work. The party consisted of an observer in 
charge of the party, one computer, one recorder, and an expert workman as observatory attendaiut. 
At the first two stations the main camp of the survey was placed at the astronomical station. 
Afterwards the camps were separated and a cook was added to the astronomical party. With 
the exception of a spring-wagon team, which was stationed with it during a small portion of the 
time as a convenient means of securing supplies and water, the party had no separate transporta- 
tion assigned to it. It was moved from station to station by the teams that served to supply and 
move the main camp. As each station was occupied for about a month this was conveniently done 
without sensibly increasing the transportation outfit of the survey. 

The instrumental outfit of the party in the field consisted of one Wurdemann zenith telescope, 
one 10-inch repeating Fauth theodolite furnished with eye-piece micrometer, four chronometers, 
one Greenough sextant and artificial horizon, and one 8 inch Coast and Geodetic Survey repeating 
theodolite carrying a 6-inch needle for measuring the magnetic declination. The Coast and 



UNITED STATES AND MEXICAN BOUNDARY. 



63 



Geodetic Survey theodolite was recalled at Nogales for use on the Coast and Geodetic Survey. 
At tliat point two 8 inch Faiith direction theodolites for use on triangulation were added to the 
equipment. A second zenith telescope was held as a reserve at tlie office of the survey. 

The work of the party from February, 1>S!>2, to February, 1893, consisted of triangulation near 
El Paso, Tex., twelve latitude and azimuth determinations between that point and Nogales, Ariz., 
small triangulations near San Pedro liiver and near Nogales, an azimuth and latitude determina- 
tion near Yuma, and another 20 miles below, and a triangulation counecting them. 

The following table shows, in condensed form, the time expended at each of the astronomical 
stations No. 1 to No. 12, El Paso to Nogales, and the observations se(!ured at each : 



station. 


From— 


To- 


Number 
ollati- 
tude ob- 
serva- 
tions. 


Number 
ofazi. 
mutli 


Remarks. 


No 1 


1892. 
Feb. 12 
Mar. 21 
Apr. 8 
Apr. 17 
May 20 


1892. 
Mar. 20 
Apr. 7 
Apr 16 


67 
39 

iR 


13 

12 

9 


.Mso trian-uLatiou. 

Do. 
Also triangulation and tangent. 




No 3 




May 19 130 
June 8 99 


No 5 






No 7 


June 30 1 July 31 99 




No 9 


Ang. 30 Sept. 29 
Sept. 30 Oct. 31 
Nov. 1 Nov. 17 


101 
106 
126 




No. 11 - 


No. 12 


Nov. 18 


Jan. 11 


121 



The dates recorded opposite each station include the time spent in moving to the next station. 
The latitude observations were all made with a zenith telescope. Each set for azimuth consisted 
of ten pointings each on star and mark with eye-piece micrometer. 

At each station the measurements of horizontal angles at the station necessary to connect the 
observed azimuth with the " tangents" ending and commencing there were made, and the magnetic 
declination was observed. 

It being considered desirable to have the results of the observations available as soon as pos- 
sible, the final computations for each station were made before leaving the station and between 
the dates recorded above. Each computation was verified by a second person before being 
accepted as final. In a few cases the latitude computation was not quite complete on leaving the 
station, but even in those cases it was so nearly complete that the result was known approximately 
and the reliability of the observations was well established. The original records were written in 
ink, and ink duplicates of them were made. 

On January 12, 1893, the astronomical party left Nogales, Ariz., by rail for Yuma, Ariz. 
Between that time and February 28 they occupied Stations No. 13 and No. 14 at Yuma and 20 
miles below, and executed a triangulation connecting those stations with each other and with 
other important points. At Yuiiia 105 observations were taken for latitude and 9 sets for azimuth^ 
and at Station No. 14, 20 miles below, 25 observations foi- latitude and 9 sets for azimuth. 

During the early part of March the astronomical party were busy with computing and other 
miscellaneous duties. About the middle of the month the party disbanded and its individual 
members were assigned to other duties on the survey. 

Between the dates September IS and October 3, 1893, Station No. 15, near Emory Monument I, 
at the Pacific south of San Diego, was occupied by myself and two assistants. Ninety-six obser- 
vations were taken for latitude and 9 sets for azimuth. 

From October 4 to December 22 I was busy with one assistant in preparing for publication 
the data of the astronomical and other determinations made under my direction during the 
progress of the survey. 



64 UNITED STATES AND MEXICAN BOUNDAKY. 

All the observations for latitude, for iiziiuiitli, for time, for niiigiietic declination, and a part 
of the observations for horizontal angles were made in person by myself. 

Mr. James Page made nearly all the original computatious. To his efficiency as an accurate 
computer is due largely the success of the adopted method of making all computations at the 
station of observation. 

Mr. H. B. Finley not only performed the ordinary duties of a recorder, but he was very efficient 
as an aid in computing and in the measurement of horizontal angles. Much of the work of verify- 
ing the original computations was done by myself and Mr. Finley working together. He observed 
most of the angles of the Nogales triangnlation and nearly all in the Yuma triangulation. 

Mr. J. S. Bilby, as expert workman, contributed largely to the comfort and success of the 
party. 

To all these gentlemen I feel greatly indebted for the zeal and cheerfulness shown by them on 
occasions when it was desirable to work during very long hours and under trying circumstances. 

All the azimuth observations were made with Fauth repeating theodolite No. 725. The 
horizontal circle, 25 cm. (10 inches) in diameter, is graduated in 5' spaces and is read by two 
opposite verniers to 5". It is furnished, on the horizontal motions, with axis clamps and tangent 
screws working against spiral springs. The telescope has a focal length of 41 cm. and an objective 
45 mm. in diameter. The eyepiece used magnifies about thirty diameters, and is furnished with 
a micrometer with which the azimuth observations were made. The standard or yoke of the 
instrument is of aluminum. 

The horizontal circle is covered with a protecting plate, which served its purpose so well that 
during two years of continuous service in a very dusty country, a part of the time on tangent 
work, so little sand and dust found its way to the graduated surfaces and the centers or spindles 
of the instrument that it was never found neccessary to take it apart for cleaning, and the 
graduation was brushed oft' but once, a discoloration having then collected on a few lines only. 

There was always an apparent yielding of the clamps and other parts when the instrument 
was used as a repeater, which caused every measured angle to be ten to twenty seconds too large 
when all final pointings were made with the tangent screws actiiuj against their opposing spiral 
springs. The yielding seemed an elastic motion, not jerky, and so nearly constant for any series 
of observations that it was eliminated, within the errors of observation, by the practice of " closing 
the horizon." 

By "closing the horizon" is meant, in this connection, measuring both the re(iuired angle and its 
explement, or difference from 360°, always turning the upper motion over the measured angle in 
the direction in which the circle readings increase and making all final ])ointings with the tangent 
screws working ogaimt their opposing spiral springs. Such a procedure gives two values for the 
required angle — the directly measured value and the difference between the measured explement 
and 300°. The mean of these two is the true value of the angle independent of the constant yield- 
ing of clamps and allied parts. 

That this method of observing sensibly eliminated the remarkably large clamp error was 
shown by the instrument giving consistent results in successive measurements of the same angle 
by the satisfactory closing of triangles in which angles were measured with this instrument, and by 
the fact that in cases in which the same angle was measured with this instrument and with a 
direction theodolite the results agreed within the errors of observation. 

For azimuth observations the theodolite was usually mounted on a wooden pier in the large 
observatory tent. The pier was a hollow triangular column, built of 3-inch pine, put together with 
screws and banded at top and bottom with heavy hoop iron. The top of the pier was covered by 
a pine plank held in place by screws and having the instrument foot-plates screwed to its upper 
surface. This cap was removed during transportation from station to station. The pier was set 
like a fence post at each station, about 45 cm. of its length being below ground. The earth was 
tamped solidly around it and its hollow interior was also filled with earth to give it greater rigidity. 
It seemed to be as stable as a brick or stone cemented pier, and its use saved much time and trans- 
portation in a region where neither cement nor water could be obtained without hauling by wagon 
over considerable distances. 



UNITED STATES AND MEXICAN BOUNDARY. 65 

The observatory tent lield both the uzimuth theodolite and the zenith telescope mounted on 
their respective wooden piers about 1.3 mm. apart due east and west from each otiier. The tloor 
space of the tent was 9 feet from north to soutli and 12 feet from east to west, and the shape of 
the tent was that of a "lean to" shed, with roof sloping downward toward the north. The sides 
and roof of the tent wt re securely supported throughout by a wooden framework. The floor was 
made so as to be portable, in six sections, and was so supported by sleepers that no pressure 
was transmitted to the ground except at the four corners of the tent, as far as possible from the 
piers. This tent served as an oflice as well as an observatory. 

The mark used for azimuth work was an ordinary bull's-eye lantern, showing through a hole 1 
inch in diameter in the front of the small box, which served to protect it from the wind. This 
light was placed from 1 to 3 miles from the theodolite at each station. 

Tlie time was obtained with sutticient accuracy for the azimuth work by sextant observations 
of the sun's altitude. 

Two mean and two sidereal chronometers were carried. Each chronometer was kept in its 
own leather case, which was inclosed in a well padded box (two chronometers in a box), and this 
box was inclosed in turn in an outer box, having a false inner top and bottom backed by systems 
of spiral springs to deaden the jarring and shocks of transportation. The rates of the chronome- 
ters proved abundantly satisfactory for the purpose for which they were used. As all the azimuth 
observations were taken near elongation, errors in time afi'ect the computed azimuth to a very 
slight degree only. 

With the exception of one station, all the azimuth observations were taken with the eye-piece 
micrometer by the method described in Bulletin No. 21, December 12, 1 890, of the Coast and 
Geodetic Survey. 

On the first night after the i)ier and tent were ready a single pointing was made upon the 
star to be used, and the time and reading of the horizontal circle recorded. The instrament was 
then left standing covered to protect it from dust and sand, with the lower horizontal motion 
clamped and the upper one loose. During the next day the upper plate was set to such a reading 
comi)uted approximately from the observation of tbe night before as would place the telescope in 
the vertical plane of the star about thirty minutes before or after the elongation near which it was 
to be observed. The azimuth light was then placed in this plane at a distance of 1 to 3 miles, 
according to the topography along the line of sight. The position of the light as thus located 
was always found to be sufliciently accurate. All observations were taken near elongation, 
usually within one hour, and Polaris was used at each station. 

The azimuth light having been previously placed nearly in the vertical plane of the star, 
the observations consisted simply of the measurement with eye-piece micrometer of the small 
horizontal angle between star and mark, tlie chronometer time of each star pointing being 
noted. For each set of observations, the axis of the telescope being made as nearly horizontal as 
possible and the horizontal circles being clamped so that the line of collimation of the telescope 
was nearly in the vertical plane of the mark, the routine was as follows: Five pointings with 
eye-piece micrometer were made upon the mark, the telescope directed to the star, and striding 
level placed in position; three i)oiutings were then made upon the star and the time of each 
noted by the recorder, the level was read and reversed; two more pointings upon the star 
with noted times, level read again; axis of telescope reversed in the wyes; striding level placed 
in position; three more pointings upon the star with noted times, level read and reversed; two 
more pointings upon star with times, and Anally five pointings upon the mark. Three such sets 
required from thirty to fifty minutes. 

At Station No. 5 the azimuth mark was placed to the westward of the station and its azimuth 
determined by using the theodolite as a repeater. 

At Station No. 10, in addition to the observations upon Polaris, S TTrsjc Minoris and 51 
Cephei were also observed. 

The graduation on the striding level is numbered from the middle toward each end. The 
eye piece micrometer was always used in the position in which increased readings of the microm- 



66 



UNITED STATES AND MEXICAN BOUNDARY. 



eter correspond to a movement of the line of sight toward the east when the vertical circle is to 
the east, and toward the west when the vertical circle is to the west. 

The computation of the horizontal angle between the mark and the mean position of the star 
during the set was made in the same way at every station, and is shown by the examples of com- 
putation given below. 

The computation of the mean azimuth of the star during the set was made by three different 
formuhi^ at different stations. For Stations No. 2 to No. 4, No. (J to No. D, No. 11, No. 13, and 
No. 14 the azimuth of the star was computed as follows: 
Let q) = the astronomical latitude of the station. 
S =the declination of the star. 
A = the azimuth of the star counted from the north. 
^, =the azimuth of the star at elongation counted from the north. 
r„ =the hour angle of the star at elongation. 
t = the hour angle of the star at observation. 

r = t^—t, or, what is the same thing, the chronometer time of elongation minus the chro- 
nometer time of observation. Then the azimuth of the star counted from tlie north is at the time 

of any observation A=A,.— sin 4, cos A,, cosec '<e~^jQ ■{" (l+^ot t,. sin t). 

A^. and t,. are computed by the formuhB sin Je = sec q) cos d and cos i^ = tan tp cot S. 

The factor sin A^ cos A^ cosec % is a constant for the night. " ^iu l"" (^ + ^Q* 'i- ^i° ^) varies 
rapidly with the hour angle, and must be computed for each separate pointing on the star. It 
varies quite slowly, however, for changes in the declination of the star and in the latitude of the 
station. This term was tabulated for an arbitrary latitude and declination of Polaris for every 
10" change in the value of r from —61"' to +61'". It was found that the values of this table were 
so nearly exact for the act^lal latitudes of stations and actual declinations of Polaris at the time 
of observation that it could be used without sensible error at all stations cited above, and was so 
used. The mean of the ten tabular values corresponding to the ten pointings on the star during 
a set being called M, the mean azimuth of the star for the set becomes 
A = Ae — sin A^ cos A^ cosec 't^ M, 

AZIMUTH DETERMINATIONS. 



ExAMi'LE OF Record and Computation. 

STATION No. 14, FEBRUARY 11, 1893, 
nbacrrat ions for azimuth of mark on Polaris near western elongation. 
= +2" 29" 47.2-; one turn of micrometer = 123,73"; one division of level = 3,68" ; * = 32o 29' 01.12" 



Circle 
E. or W, 


Level readings. 


Chronometer 


^ 


Tabu- 
lated 
term. 


Micrometer readings. 




W. E. 


time. 


On star. 


On mark. 


E 


d. 
7,2 


d. 
6.3 
6.4 


h.m. s. 
8 47 48. 5 

48 31.0 

49 01. 5 

49 47.0 

50 20.0 

8 52 09.0 

52 36. 5 

53 04. 5 

53 57. 5 

54 28.0 


.57 34.5 
5C 52. 
56 21. 5 
55 36. 
55 03. 

53 14.0 
53 46. 5 
52 18. 5 
51 25. 5 
50 55. 


6496.9 
6338. 5 
6226.3 
606O.3 
5941.2 

5556. 9 
5461.9 
5366. 1 
5187.0 
5084.8 


>. 
19.219 

.189 
.170 
.146 
,124 


18.400 
.391 
.387 
,399 
.393 


I.ollj;. 21' 31" W. of 
Wa.sliington. 

Means. 
Means. 


+ 14,4 


-12,7 


W 

W 


6,0 
6.1 


8.0 
7.8 


19. 1696 


18,3940 


17.790 
.800 
.820 
.852 
.871 


18,470 
.470 
,469 
.475 
.462 


+12.1 
—2.0 


-15.8 
= Suin. 








5772.0 


17.8266 1 18.4692 



UNITED STATES AND MEXICAN BOUNDARY. 67 

a of Polaris = l" 18"' 4^;< 
5of Polaii8 = 88o 41' 33. 4 " 



log tan <p =9.8039137 


log sec <p = 0.0738919 


log cotiind' =8.3414167 


log cos 5 =8.3413121 


log COS te =8. 


1453304 


log sin Ae=8. 4152040 


tc = 89 


o 11' 


' 57. 5" 


A,= l"29'26.34" 


t„ =5" 


56- 


47. 8=^ 




log sin Ae =8.41520 




Con 


istant for eiglit readings of level r^''' ^* tan <z. = 293' 


log cos A, = 9. 99985 






8 


log cosec J t,. = 0.00008 




Lev 


el correction = (—2.0) (0. 293) = 0. 59" 


8. 41513 








log 5772. =3. 7t;i33 









log 150.13 =2.17646 
th distance of star = 57- 09' (by computation). 



= 18.4316' 








= 0.0376 = 







04.65 


= 0.7380 








= 0.6050 








= 0.6715 = 




1 


38. 90 


= 






— 0.59 


= 


1 


42.96 


= 




2 


30.13 


= 


^ 


7 


47.17 


= 


1 


29 


26.34 


= 


1 


28. 


39. 17 




78 


31 


20.83 



1 18 48.0= a 
+ 5 56 47.8 = t, 
+ 2 29 47. 2 = i-hrononieter error. 

9 45 23. = chrouoiiieter time of elongation. 
Collimation reads, + (18.3940' + 18.4692') 

Mark west of collimation, 18.4316' — 18.3940' 

Circle east, star east of coUimiition, 19.1696' — 18.4316' 

Circle we.st, star east of collimatiou. 18.4316' — 17.8266' 

Mean, star cast of collimation, 

Level correction, 

Mark west of star. 

Reduction to western elongation, 

Mark east of western elongation, 

A,. 

Mark west of north, 

Mark west of south, = z' 

In reducing the measured ano;le between the star and the line of collimation it must be remem- 
bered that the thread of the microuieter when not at the collimation reading describes a small 
circle on the celestial sphere as the telescope rotates about its horizontal axis. 

Thus, star east of collimation = 
().67ir)' = (0.f)7ir.) (1.2.373) cosec (zenith distance of star) = (0.6715) (1.2373) cosec 57° 09'=1'38".90. 

In reducing the measured angle between the mark and the line of collimatiou cosec (zenith 
distance of mark) may usually, as here, be assumed unity without sensible error, the elevation 
angle of the mark being generally small and the line of collimation being purposely placed very 
near the mark. The level correction for the mark is usually negligible. 

At station No. 1 the azimuth of the star was computed by the less accurate but simpler 
formula: 

2 sin- i r , 

At this station no observation was made more than 26'" from elongation, and this formula was 
sufficiently accurate. 

At Stations No. 5, Xo. 10, No. 12, and No. 1,5 tlie azimuth of the star was computed by the 
following formuhe: 

If A be the azimuth of the star, counted from the north, corresponding to the mean horn- 
angle of the set, t, 

. . sin t 

~cos q) tan 6 —sin (p cos t 
If A' be the mean azimuth of the star for the set, counted from the north 

A'=A-tanA^2 ^.^^„ 



68 UNITED STATES AND MEXICAN BOUNDARY, 

in which n is the nnmber of pointings npon the star during the set, 



here the difference 



between the time of any one observation and the mean of tlie times, and 2 



, 2 sin^ i T . 



"r IS the snm of 



the individual values of that factor corresponding to the individual pointings. The quantity 
— ■ %- may be found tubulated in convenient form in Doolittle's Practical Astronomy. For this 
and other formula? for reducing azimuth observations see Coast and Geodetic Survey Report for 
1880, Appendix No. 14. 

STATION NO. 10, OCTOBER 13, 1892. 

Ohservjlionsfor azimuth of mark on Polaris near eastern elongation. 

rChronometer error = + 2i' ll" 28.2>; one turn of micrometer = 123.73" ; one division of level = 3.68" ; </. = 31° 19' 35".] 



Circle 
E. or W. 


Level re.iding8. 


Chronome 
ter time. 


^ 


2 8in^ § T 

ViHi"- 


Micrometer readings. 




W. 1 E. 


On star. 


On mark. 




d. 


d. 


h. m. .<,. 


m. ». 




t. 


(. 




E 


8.0 


9 9 


9 00 38.0 


3 58. 


31.05 


18. 379 


18.310 


Long. 2'' 12™ west of 




10.0 


7.3 


07 32. 


3 04.6 


18.59 


.3S8 


.315 


Washington. 




+18.0 


—17.2 


08 05. r, 

09 13 


2 31.1 
1 23. C 


12.45 
3.82 


.400 
.421 


.315 
.311 




E 






09 48. 
9 12 01.8 


48.6 

1 25.2 


1.29 
3.96 


.430 


.316 


Means. 


W 


9.0 


9.0 


18. 4042 


18. 3134 


18. 100 


18.290 




7.0 


10.9 


12 24. 7 

12 48. 3 

13 30. 3 


148.1 
2 11.7 
2 59. 7 


6.37 
9.46 
17.61 


.100 


.275 
.279 
.281 




+16.0 


-19.9 








13 58. 1 


3 21.5 


22.14 


.080 


.279 


Means. 






d. 
—3.1 


9 10 30.6 


12.67 


18.0912 


18.2808 




Sum 















a of PolariB = 1" 20'" 07. 4^= 

i5 of Polaris = 88° W 10.4" 

Constant for eight readings of level = ^ (3.68") tan <p ^= 0.28 

Zenith distance of star at observation (computed) = 58° 47' 

log y 2i«'" ^^ ' 

log tan A 



log S A 
5 A 



= log 



;.67 = 1. 10278 
= 8. 4096 



= 9. 51247 

= 0.33" 

CoUimation reads, i (18. 3134' — 18. 2808') = 18. 2971' 

Mark east of collimation, 18. 3134' — 18. 2971* = 0. 0163 = 

Circle east, star east of collimation 18.4042 — 18.2971 = 0.1071 
Circle west, star east of collimation, 18. 2971' — 18. 0912' = 0. 2059' 
Mean, star east of collimation, 
• Level correction = (— 3. l<i) (0. 280) 



Mark west 



8tn 



Mean chronometer time of obs 
Chronometer correction 



Mean sidereal time of observati 
S of Polari.s 







= 0.1565 = 


22". 64 






= 


-0".87 






_ 


19". 75 


h. 


HI. 


8. 




21 


10 


36.6 




-2 


11 


28.2 





log COS <p = 9. 9315695 
log tan S =l.t!56381."> 



= 95° 14' 45. = 
log sin <p = 9. 71593 
log cos t = 8. 96108 I 



5 8. 67701 n 
'( -0. 04753 



d = 38. 72140 — (—0. 04753) = 38. 

Star east of north 

Mark west of star ( from aliove) 

Mark west of south 



20 59.0 

log sin t ^ 9. 9981771 
log d =1. 



log tan A = 8. 
A = 1' 
5 A = 



UNITED STATES AND MEXICAN BOUNDARY. 69 

The same remarks as before apply to the reductiou of the augle between star and collimation 
and mark and collimation. 

To all the azimuths as above computed there must still be applied the small correction 
+0.31" for dnirnal aberration. For convenience this small correction ^yas applied only to the 
final mean value of the azimuth at the station instead of adding it to each individual value 
Hence the symbol c' has been used for the computed azimuth as above before the correction f(u' 
diurnal aberration has been applied and z denotes the corrected azimuth. 



station. 


Date. 


Star. 


z' 


Mean z' 
for night 


X°'' -for 
staSon. 1 «»»«»-• 


e and e,. 


No. 1 


18'.I2. 
Feb. 16 
....do.. 


1 : 


178 30 40. 7a 
30,96 


" 


" 




No. 1 




1 




No. 1 


....do.. 


39.99 
39. 02 


40. 25 






No. 1 


Feb. 18 




e = ±0.46 

6..= ± 0. 21 






39. 80 40. 11 




Mar. 22 




No- 2 


36.34 
38.06 
36. 09 
37.97 
178 31 48. 31 
47.19 
47.27 
40.52 
46.44 
1 26 16. 65 
15.33 
17.83 
15.78 
14.22 
15.29 

27.8 
29.12 


1 






No. 2 


do .. 










No. 2 










e = ^ 0. 56 

e.= ± 0. 25 






37.15 


37.15 


37.46 


No. 3 


Apr. 9 












No. 3 


....do.. 




















e = + 0. 50 
eo= ± 0. 23 


No. 3 ..... 


.-.do.. 
Apr. 18 
do .. 


47.15 


47.15 


47.46 


No. 4 


15.99 








No. 4 


Apr. 21 
do 


° 

I 








No 4 








e = ±0.83 
eo=±0.34 

Using the. 

odolite as a 


No. 4 




No. 4 

No. 5 


....do.. 
May 22 
....do... 


15.78 


15.85 


16.16 


No. 5 








No. 5 


do .. 


26.8 






No. 5 


May 24 
....do ... 








No. 5 


29.4 
28.6 
27.3 
1 23 12.48 
11.18 










No. 5 

No 5 .. 


-•::•■■ 








e„= ± 0. 7 


27.4 


27.1 


27.4 


No. 6 


June 10 
....do... 


No. 6 











No. 6 


....do ... 


11.10 
11.87 
11.17 
12.26 
12.56 
12.14 
12.92 
13.21 
13.69 
14. 34 
15.15 
181 27 53. 94 
54.87 
54.97 
53.83 
55.93 
55.16 
55.81 
65.07 
56. 12 

55,97 
55.65 










No. 6 


....do... 










No. 6 

No. 6 


....do ... 










11.68 








No. 6 


June 12 
....do... 








No. 6 










No. 


...do ... 










No. 6 


...do... 










No. 6 












No. 6 


...do... 








e = i 0. 83 


No. 6 




13.43 


12.62 


12.93 


No 7 


July 7 
...do... 


No. 7 

No. 7 










No. 7 


...do... 


54.40 




1 


No. 7 


July 8 
...do... 




, 1 


No. 7 










No. 7 

No. 7 


...do... 
...do... 






1 




55.49 








No. 7 


July 9 
...do... 








No. 7 










No. 7 


...do... 






e=±0.50 
e.= ± 0. 14 


No. 7 


...do... 


55.74 1 55.21 


..5.52 



70 



UNITED STATES AND MEXICAN BOUNDARY. 
Summary— Continued. 





1892. 




Aug. 2 
....do ... 


No. 8 




....do... 


No. 8 


....do... 




Aug. 3 
....do ... 


No. 8 




Aug. 4 
....do .. 


No. 8 


No. 8 


....do... 


No. 8 


....do... 




Sept. 10 
....do... 


No. 9 




....do... 


No. 9 


....do... 




Sept. 12 
....do... 


No. 




....do... 


No. 9 


....do... 




Sept. 14 
....do ... 


No. 9 




....do... 


No. 9 




No. 10 


Oct. 5 


No. 10 


....do... 




....do... 


No. 10 


Oct. 10 




....do... 


No. 10 


....do ... 






No. 10 


....do... 




....do... 


No.lO 


Oct. 5 






No 10 


do 






No 10 


do 




....do... 


No.lO 


Oct. 13 




....do... 


No.lO 


....do... 


No. 10 


Oct. 5 


No. 10 


....do ... 






No.lO 


Oct. 10 


No.lO 


....do... 


No.lO 


....do.. 






No.lO 


....do.. 


No.lO 


....do.. 














No. 11 


Nov. 7 






Noll 


....do.. 


No. 11 


Nov. 8 




do 




1 


No. 12 


Dec. 3 






No 12 


do 


No. 12 


Dec. 5 



1 32. 10 
33.00 
31.50 
31.80 
30.99 
31.85 
31.19 
30.14 
30.41 
32.31 

I 11.79 
12.22 
12.99 
12.18 
12.76 
13.92 



12.85 
12.41 

' 55.35 
55.38 
55.28 
55.81 
50.35 
56 23 
56.81 
56.83 
56.63 

! 51. 29 
52.49 
52. 72 
52.95 
52.07 
52.26 
52.14 



52.; 



18.52 
19.33 
20.17 
19.87 
20.32 I 
21.72 



28.09 
30.26 
28.22 



32.10 
31.42 



UNITED STATES AND MEXICAN BOUNDARY. 
Summary.— Continued. 



71 



station. 


Date. Star. 


z' 


Mean z- 
for night. 


Mean z' 

for 
station. 


zfov 
station. 


eande„. 


No 12 


1892. 
Dec. 5 
....do... 




178 33 39.71 
38.93 
37.03 
38.80 
37.79 

178 32 01. 67 
00.87 
00.50 
00.99 
01.17 
00.11 
59.67 
01.47 
00.86 

178 31 20.83 
19.86 
20.02 
21.48 
21.84 
18.84 
21.32 
20.83 
21.27 

181 28 37. 39 
37.99 
37.92 
39.89 
38.79 
38.77 
41.31 
39.92 
38.91 






" 


" 




39.63 










Dec. 8 
do 
















e =±0.77 






37.87 


38.88 


39.19 




1893. 

Jan. 21 

do 


No 13 














01.01 








No 13 


Jan. 22 






















00.76 









No 13 


J." 23 


1 








1 


e = + 0.42 
e. = ±0.14 


No 13 


do 


00.67 


00.81 01.12 




Feb. 11 

....do... 

do 


No. 14 








20.24 








Feb. 13 
do 


1 




No 14 














20.72 








No 14 


Feb. 14 














e. = ±0.21 


No. 14 


....do... 

Sept. 21 
do 


21.14, 20.70 


21.01 


No 15 








No 15 


do 


37.77 










Sept. 22 
do 










No 15 












39.15 








No. 15 


Sept. 23 














e =±0.81 
&, = ±0.27 


No. 15 




40.05 38.99 39.30 



The values of the above summary represent in each ca.se the azimuth (west of south) of the 
mark as seen from the station. At Stations No. 4 and No. 6 the mark was placed to the mxith- 
ward of the station nearly iu the verticil plane of the star. In tho.se cases the topography was 
such that an azimuth light could not be placed at a sufiQcient distance to the northward of the 
station. Placing the light to the southward does not materially modify the method of observation 
or cause any especial inconvenience. 

At Station No. 10 three marks were used, cue for each star. 

In the above summary "«" indicates a Ursie Minoris (Polaris), " f?" indicates S Ursie Minoris, 
and "510" indicates 51 Cephei. 

All the observations were made by the micrometric method save those at Station No. 5. 

The values of the probable error of a single set (e) and the probable error of the mean for the 
station (e„), as given above, are computed by the ordinary formula' for independent observations 
of equal weight. In reality, however, several azimuth observations made on any one night at 
nearly the same time of night are likely to be affected by a considerable error common to them all, 
a constant error peculiar to the night, which is probably the result of lateral refraction. Therefore 
several sets of observations taken in quick succession should not be considered to be independent. 

The values of e given above are for that reason slightly too small, and the values of e„ much too 
small to represent the facts. They serve, however, as a rough indication of the relative accuracy 
of the determinations at the different stations. 

The probable error of observation and the error peculiar to the night of observation may be 
separated by the same method that is used in computations of zenith telescope latitudes for 
separating the errors of observation from the errors of declination. 



72 UNITED STATES AND MEXICAN BOUNDARY. 

Let e be tbe probable error of observation of a single set, J be the difference between the 
value from each set.and the mean for the night, A,, be the difference between the mean for each 
night and the mean for the station, and e,„ the probable error of the mean result for a night. 

Let e„ be the probable error peculiar to the night, affecting eciually all the results for that 
night. 

Then e and e„ may be derived from observations at a series of stations treated as a single 
group, as follows : 



4 



(0.455) JS A^ j^.,^ e- ^ 1 

No. sets — No. nights No. nights n 



-E^ 



in wliich n is the number of sets on each night. 

_ / [^MW^A^ZH e„=Je 

"' V No. nights— No. stations v 

All the observations for azimuth made with the micrometer (all stations except No. 5) when 
treated as a single group in this way give for the probable error of observation of a single set 
e=±0.54", and for the probable error peculiar to each night ^,,= ±0.38", 

It is pi'obable that the conditions under which these observations were made— in a very dry 
country, over surfaces usually free from water and bare of trees, and with the meteorological 
conditions subject to few sudden changes— are peculiarly favorable to making the value of e„ small. 
It is likely that it would be larger in most regions than it is for this series of stations. 

With these values the probable error of the mean at a station at which three sets were 
observed on each of three nights is 

^J(0.54f+|(0.38f-±0.28" 
The value of one turn of micrometer was observed four times: 

At El Paso, February 8, 18.(2, one turn = 123.9i. 

At Station No. 1, February 19, 1892, one turn = 123.80. 

At Station No. 1, February 19, 1892, one turn = 123.44. 

At Station No. 6, June 11, 1892, one turn = 123.70. 

The first determination was made by measuring a small horizontal angle (about I -) with both 
the micrometer and the horizontal circle of the instrument. The second was made by observing 
transits of e Urs;e Minoris near culmination across the thread set successively at each half turn. 
The third and fourth determiuatious were made in a similar nninner, using 6 Ursie Minoris and 
Polaris, respectively. Tlie mean of the first three determinations, namely, 123.72", was used at 
the first five stations. After that the mean of all four de'erminations, 123.73", was used. 

At each station the angle between the star and mark at the time of observation was so small 
that any error of micrometer value has but a small influence upon the computed azimuth. For the 
third set on June 10, 1892, at Station No. G, the angle as measured with micrometer between 
the star and the mark was 2.93 turns, and tlie computed azimuth from that single set is in error 
by 2.93 times the error of the assumed value of one turn. Similarly the final mean value for the 
azimuth of the mark at that station is iu error by 2.19 times the error of one turn. 

In this connection it should be noted that the value of micrometer as redetermined at this 
station agreed almost exactly with the mean of the previous determinations. At all other 
stations except No. 6 the mark was in such a position that in very few cases is as much as one 
turn of micrometer used, and in most cases less than one-half of a turn, the star being also both 
east and icest of the marh during different sets. 

For the stations occujned the motion of Polaris in the azimuth even at one hour from elonga- 
tion is only about one-tenth of a second of arc per second of time. As almost all the azimuth 
observations were made within less than one hour of elongation the errors arising from errors of 
time must be quite small. The error of the chronometer at the time of observing azimuth was 
always computed from sextant observations of the sun taken both before and after the azimuth 
observations. 



UNITED STATES AND MEXICAN BOUNUARY. 73 

The value of one division of the striding level was determined to be 3.(38" by comparing it 
with the latitude level of Wurdemann zenith telescope No. 20. During the fomparison the strid- 
ing level was lashed tiimly to the latitude level and the whole combination moved by the use of 
the screw which changes the inclination of the telescope. 

The observations at each station all being taken near one elongation the azimuth is in error by 
the error of the star's declination. 

In order to determine whether there was any sensible error ))eculiar to the star Polaris, 
which was uniformly used at all stations, d Ursir Minoris and 51 Cephei were also observed at 
Station No. 10 on the same nights as Polaris and in precisely the same manner. A separate 
azimuth mark was used for each star. The three marks were reduced to the same pole, A, by 
measuring the angle at the station between each mark and the pole. 

Three sets for azimuth were taken on each star on each of three nights as shown in the above 
sunnuary. The errors of observation seemed to be about the same for each of the three stars — 
being perhaps a little smaller for Polaris than for the other two. The probable error of the 
azimuth of each mark from nine observations on three nights may properly be considered to be 
±0.28". 

The horizontal angle between each mark and i)ole A was measured twenty times with the 
theodolite used as a repeater, each measure consisting of six repetitions on theieiiuired angle and 
six on its explement. These measures gave a range of live to six seconds on each angle — the 
seeing being unsteady during most of the observations. At this station the violent appai'enf 
trembling of signals commenced almost immediately after sunrise and ended very nearly at 
sunset, leaving but a few minutes of steady seeing during the day. To have observed under 
favorable circumstances only would have recjuired more time than was then at the disposal of the 
party for experimental work. 

The mean results are : 



Keduction to j 



Polaris. 


6 UrsiB Minoris. 


51 Cephei. 


181 27 56.39 ±0.28 
-50 06 56. 16 ± 0. 25 


170 02 52.31 ±0.28 . 
-50 41 51.43 ±0.30 


183 15 20.12 ±0.28 
—57 54 18. 25 ± 0. 31 


125 21 00.23 ±0.38 


125 21 00.88 ±0.41 


125 21 01.87 ±0.42 



The accuracy of the three results does not seem to be sufficient to insure that the differences 
between them are not accidental differences. 

Having determined the azimuth of the mark, the problem arose of placing a point to the 
westward exactly in the prime vertical of the station — said point serving with the station to fix 
the direction of the "tangent'" to be continued forward to the next station. A point was first 
placed as nearly in azimuth 90° as could be done by a single pointing and reading of the horizon- 
tal circle — usually within ten seconds. The distance to this point from the station was measured 
by chain or stadia, and the angle between the point and the azimuth mark was measured with the 
theodolite used as a repeater — each set of observations consisting of six repetitions on the angle 
and six on its explement. The linear correction at right angles to the line of sight necessary to 
place the point in the prime vertical of the station was then computed and the final point set by 
linear measurement from the a])proximate point. 

In some cases, in which it was not convenient to measure by chain or stadia the distance to 
the approximate point, two approximate points were placed nearly in the prime vertical and at 
the same distance from the station. A linear measurement was made of the distance between the 
two points and the angle between each of them and the azimuth mark was observed. The final 
point was then located by linear measurements only from the two approximate points. 

LATITUDE DETERMINATIONS. 

All the latitude observations were made with Wurdeman zenith telescope No. 20. This 
instrument was formerly used on the Northern Boundary Survey from the Lake of the Woods to 
the Rocky Mountains. It was thoroughly cleaned and repaired by Fauth & Co., at Washington, 
S. Doc. 247 !) 



74 



UNITED STATES AND MEXICAN BOUNDARY. 



D. C, in December, 1891. The microiaeter was there remodeled, and the old micrometer screw 
replaced by a new one of about the same pitch, 100 txirus to the inch. The latitude levels were 
also replaced by new ones. 

The principal dimensions of the instrument are: Clear diameter of objective, 67 mm.; focal 
length, 826 mm.; diameter of vertical circle, Hi mm., and side of equilateral triangle formed by 
foot screws, 368 mm. The eyepiece used magnifies about seventy diameters. The vertical circle 
is graduated to fifteen minute spaces and its vernier reads to half minutes. 

The latitude level carries a 2 mm. graduation of 70 divisions, numbered continuously from one 
end to the other. The graduation nearest the eyepiece in the position in which the instrument 
was always used is marked "0" and the one nearest the object glass "70." The level tube is 
protected from sudden changes of temperature by an outer glass tube. 

The instrument was always used in the position in which increased nucrometer readings 
correspond to increased zenith distance of the object observed. The clamp for vertical motion of 
the telescope is an axis clamp. The time was computed from sextant observations of the sun's 
altitude. 

The instrument was usually mounted on a wooden pier similar to that used for the azimuth 
instrument, but larger and heavier. The footplates supporting the foot screws of the instrument 
were screwed fast to the end of the pier without the intervention of any cap, the upper end of 
the hollow pier being left open. This pier was placed in position in the large observing tent in 
the manner described in connection with the azimuth instrument. At Nogales and at Yuma the 
zenith telescope was mounted upon the brick pier which had previously been used as a latitude 
pier by the Coast and Geodetic Survey longitude party. 

In the following tables, showing the latitude observations, the star numbers, unless they are 
otherwise indicated, refer to Prof. T. H. Safford's list as published elsewhere in this report. Star 
numbers preceded by the letter "P" refer to Preston's Hawaiian list for 1887, Coast and Geodetic 
Survey Eeport for 1888, Appendix No. 14. Stars whose mean places were taken from the Ameri- 
can Ephemeris are indicated by the letter "E" and the name of the star. Similarly stars from 
the Berliner Jahrbuch are indicated by their names and the letter "J." 

Tliese references will not only serve to identify each star, but to show the authority from 
which its mean place was taken. The Safiford star places were furnished as needed, and in some 
cases the place furnished for a star at a later date differs slightly from that previously used. 
The notes as to mean places at the end of the published latitude record for each station cover all 
such cases. The differences between the places as there given and the published list are very 
small, and their effect upon the mean latitude for the station would hardly be appreciable. 

station Xo. 1, 4 miles aboce El Paso, Tex., near Monument No. 1. 



•23. 180 
20. 240 
20. 070 
19. 88:i 
20. 129 j 
21.769 



19. 490 
19. 029 
20. 169 



31.418 
20.044 
24.410 



Star ^ „. o 
Tj„ JN . or s. 



41.0 
50.9 
49.3 
21.0 
17.9 



13.4 
54.3 I 
49.8 



Microm 

eter 
reading. 


Level 

N. : S. 


Latitude 
31° 46' 


I. 


d. 


.. 




18.601 


49.8 


16.0 


57.21 


20. 401 


14.5 


47.4 


59.33 


20. 112 


9.9 


58.2 


59.51 


20.050 


22.0 


54.0 


59. .32 


20.242 


17.9 


53.2 


59.18 


18. 720 


40.0 


7.0 


58.86 


18.393 


62.9 


14.1 


57.66 


18.081 


53.7 


18.0 


59.30 


21.233 


46.1 


13.0 


58.36 


20. 410 


61.9 


13.0 


58.25 


20.398 


46.0 


13.9 


59.33 


21.024 


46.2 


10.4 


59.28 


11. 190 


23.9 


57.2 


58.68 


10.184 


5.2 


36.9 


59.25 


10. 741 


19.2 


52.3 


58.58 


11.655 


11.8 


47.8 


59.38 


11.210 


5,5.8 


22.0 


59.10 


15.691 


54.9 


22.9 


59.06 



•295 observed 27 ■ late; Feb. 18, 



UNITED STATES AND MEXICAN BOUNDARY. 

Station Xo. 1, 4 miles abore El Paso, Tex., near Monument No. 1 — Continued. 



75 



tar 


No.orS. 


30a 


S. 


302 


s. 


304 


N. 


304 


N. 


304 


N. 


304 


N. 


30G 


N. 


306 


N. 


306 


N. 


308 


N. 


308 


N. 


308 


N. 


308 


X. 


310 


N. 


310 


TS. 


310 


N. 


310 


N. 


312 


S. 


312 


s. 


312 


s. 


312 


s. 


314 


s. 


314 


s. 


314 


s. 


314 


s. 


317 


s. 


317 


s. 


317 


s. 


322 


s. 


322 


s. 


322 


s. 


322 


s. 


326 


N. 


326 


N. 


329 


N. 


329 


N. 


329 


N. 


329 


N. 


331 


N. 


331 


N. 


331 


N. 


339 


N. 


339 


N. 


339 


N. 


343 


N. 


343 


N. 


343 


N. 


347 


N. 


347 


N. 


347 


X. 



Microni. 

eter 
reading. 


Level 


^: 


No.orS. 


Microm- 
readlog. 


Le 


•el 




N. 


S. 


N. 


S. 


31° 46- 


t. 


.. 


d. 






,, 


d. 


d. 




24.133 


16.6 


49.8 


303 


N. 


15.279 


48.1 


14.9 


59.15 


24.031 


11.0 


47.5 


303 


X. 


1.-.. 2.59 


49.0 


12.8 


59.59 


15.019 


51.3 


17.9 


305 


s. 


24.769 


16.5 


.50. 1 


60.28 


15.060 


50.6 


18.4 


305 


s. 


24.709 


12.8 


45.0 


59.97 


15.664 


51.5 


17.9 


305 


s. 


25.431 


18.0 


52.0 


60.05 


15. 532 


.'52.3 


15.9 


305 


s. 


25. 230 


14.2 


51.0 


59.86 


17.637 


51.3 


17.5 


307 


s. 


23. 139 


15.9 


49.5 


09.81 


18. 350 


50.9 


18.0 


307 


s. 


23. 809 


16.4 


49.1 


58. .57 


18. 372 


50.9 


16.4 


307 


s. 


23. 938 


17.9 


62.0 


60.17 


29.500 


54.0 


20.1 


309 


s. 


8.730 


18.9 


52.8 


59.40 


30.547 


49.7 


17.0 


309 


s. 


9. 759 


14.8 


47.0 


59.52 


29. 792 


53.2 


19.0 


309 


s. 


o.oeo 


20.0 


54. 8 


59.23 


30.376 


47.0 


10.2 


309 


s. 


9.570 


9.2 


46.0 


59.03 


15. 939 


49.1 


15.0 


311 


s. 


22. 917 


12.0 


46.0 


60.94 


16.221 


52,1 


19.2 


311 


s. 


23. 180 


16.9 


49.9 


59.88 


16. 161 


52.0 


17.2 


311 


s. 


23. 181 


18.9 


53.3 


59.55 


16.018 


50.1 


13.1 


311 


s. 


22. 960 


11.0 


48.0 


59.79 


30.855 


16.9 


50.9 


313 


X. 


11.049 


52.8 


18.5 


59.20 


30.205 


18.0 


51.1 


313 


X. 


10. 431 


53.0 


19.9 


60.27 


30. 621 


20.7 


55.3 


313 


N. 


10. 757 


.55.1 


20.0 


59.87 


30.592 


14.2 


51.4 


313 


X. 


10.721 


49.2 


12.1 


59.71 


K.6P5 


23.0 


57.1 


315 


X. 


22.248 


61.2 


26.9 


60.32 


17.409 


18.5 


51.9 


315 


X. 


21.938 


53.4 


20.0 


59.86 


18. 348 


18.3 


53.3 


315 


X. 


22.878 


53.3 


18.1 


58. 96 


18.873 


15.0 


52.1 


315 


X. 


23.364 


49.3 


12.0 


58.95 


25.491 


21.0 


54.8 


319 


X. 


15.801 


56.0 


22.1 


59.12 


25.078 


17.6 


52.7 


319 


X. 


15. .359 


52.5 


17.0 


59.22 


24. 782 


13.0 


50.2 


319 


N. 


15.001 


46.4 


9.0 


59.58 


9.393 


16.3 


51.1 


324 


X. 


31.728 


53.3 


18.3 


58.95 


9.167 


17.8 


51.4 


324 


X. 


31.462 


53.2 


19.2 


59.95 


9.179 


16.5 


52.0 


324 


X. 


31.470 


52.7 


17.0 


60.17 


9..'i35 


11.2 


48.9 


324 


X. 


31.84S 


49.9 


12.0 


59.65 


27.641 


52.0 


18.0 


328 


s. 


11.538 


16.5 


50.7 


59.62 


27.912 


51.2 


13.4 


328 


.s. 


11.780 


13.0 


50.8 


58.59 


19. 798 


52.8 


17,8 


330 


s. 


20. 651 


13.2 


48.5 


59.13 


19.680 


50.0 


15.9 


330 


K. 


20. 601 


13.0 


47.1 


60.09 


20.442 


56.1 


20.2 


330 


s. 


21.391 


20.0 


55.6 


59.62 


20.518 


54.2 


16.1 


330 


s. 


21.431 


14.7 


52.4 


59.67 


22. 141 


50.9 


16. -, 


334 


s. 


18.761 


14.0 


48.8 


58.83 


21.601 


48.8 


13.0 


334 


s. 


18.238 


11.3 


47.3 


59.04 


21.028 


56.4 


IS.: 


334 


s. 


18. 598 


17.7 


55.8 


60.03 


16.240 


49. G 


14.0 


340 


s. 


23.417 


11.9 


47.2 


59.16 


17.013 


50.4 


l.i.O 


340 


s. 


24. ICO 


13.4 


48.2 


58.31 


16. 667 


50.9 


12.5 


340 


s. 


23.862 


11.2 


49.8 


59.69 


9.251 


46.9 


12.0 


345 


s. 


29. 760 


9.0 


44.0 


60. .39 


9.398 


48.0 


11.9 


345 


s. 


29. 892 


11.5 


47.8 


58.29 


9.390 


56.1 


17.9 


345 


s. 


29.911 


10.9 


55.1 


59.74 


24.313 


5U.5 


15.0 


349 


s. 


17.348 


12.0 


47.8 


59.36 


23.982 


.50.9 


16.0 


349 


s. 


17. 061 


13.9 


48.7 


60.32 


23. 360 


55.0 


10.5 


349 


s. 


16. 401 


15.2 


•54.0 


58.92 



Feb. 15, 8 
late; Feb. 27, s 
late; Feb. 27, si 
lale; Feb. 18, s 
late; Feb. 18, s( 

One (livii 
Total, 67 
Latitude 
Latitude 



27. 



tar 308 observed 12 • late ; Feb. 27. star 308 observed 22 • late ; Feb. 15 star 310 observed 30 ■ late ; Feb. 16, star 310 observed 26- 

tar 310 observed 10 ' late ; Feb. 15. star 314 observed 6 > late ; Feb. 16, star 317 observed 24 " late ; Feb. 18, star 319 observed 8' 

tar 319 observed 24- late: Feb. 15, star 322 observed 20' late; Feb. 16, star 322 observed 20- late; Feb. 18, star 322 observed 20' 

tar 324 observed 70- late; Feb. 15, .star 329 observed 45 ■ late ; Feb. 15, star 330 observed 8 • late; Feb. 16, .itar 329 observed 11" 

tar 329 observed 34 > late; Feb. 15, .star 339 observed 6- late: Feb. 15. star 340 observed 25- late; Feb. 16. star349ol)served 16' late. 

of micrometer = 02.225". 

iion of level = 1.28". 

observations on 19 pairs. 

of Station Xo. 1 =31^ 46' 59.40" ± 0.06", 

of Monument Xo. 1 = 31° 46' 59.40" + O.OC". 

of Station Xo. 1 was about 4 miles above El Ta.so. Tex., just e;.st of tbe Rio Grande, near tbe Atchison, Topeka and Santa Fe 

meters east and 0.0 meter north of Monument Xo. 1. 

erved four times were given weight 1, three times 0.8, :ind twice 0.0. 



76 



UNITED STATES AND MEXICAN BOUNDARY. 
station No. :1, near Monument Xo. IS. 



Microm- 
eter 
reading. 



17. 9BU 
30.959 



9.731 
28. 530 
20. 505 
22. 482 
10. 531 
13.352 
13.012 
21.850 
16.341 



■ 19. 918 
25.700 
22*004 
29.521 
13.269 



27. 352 


15.5 


14. 824 


47.9 


22. 387 


53.2 


25. 491 


49.9 


21.061 


50.1 


20. 931 


17.0 


30. 691 


46.9 


24. 930 


21.0 


16. 257 


49.9 


30. 228 


13.5 


17. 151 


61.1 


24. 630 


50.0 


18. 459 


45.9 


23. 770 


46.9 


13.530 


15.9 


33.052 


15. « 


20. 339 


52.1 



23.392 


15.8 


48.9 


10. 120 


19.3 


62.8 


24. 001 


20.7 


64.0 


23. 400 


47.0 


13.6 


18. 091 


50.9 


17.0 


32.110 


49.0 


14.9 


12.428 


16.0 


50.8 


21.403 


14.5 


49.1 


19.089 


15.6 


50.1 


31. 070 


17.0 


53.8 


28.732 


48.2 


14.9 


26. 662 


15.8 


49.7 


18.321 


13.5 


47.4 


24. 049 


14.1 


48.2 


25. 738 


17.7 


r.2.0 


14. 540 


48.0 


13.9 


25. 069 


14.9 


49.0 


19.710 


20.0 


.50.3 


15.879 


19.2 


.50.0 


21. 119 


17.0 


48.0 


21.819 


49.1 


17.0 


10.859 


13.9 


46.6 


16.178 


55.0 


21.9 


25.920 


14.9 


49.0 


10. 481 


.50. 


15.0 


24. 252 


13.0 


49.1 


17. 605 


11.3 


47.7 


22. 537 


7.7 


43.8 


17. 748 


0.8 


40.2 


29. 6.51 


53.6 


16.0 


8.100 


55.0 


17.0 


22. 333 


13.0 


51.0 


13.577 


54.2 


10.1 


30. 300 


56.4 


18.8 


23. 039 


54.0 


16.1 


15.441 


52.0 


14.0 


18.011 


51.9 


13.9 


12. 137 


11.1 


49.2 


28.164 


46.1 


19.9 



60.27 
60.44 
59.57 
61.26 
60.46 
59.96 



Mar. 21, star 310 observed 29 ' late ; Mar. 21, star 314 observed 12 • late ; Mar. 21, 

Mar. 21, star 329 observed 54 -Lite; Mar. 21, star 343 observed 46' late; Mar. 21. 6 

Mar. 21, star 393 observi-d 13 " late i Mar. 21. star 399 observed 13 • late ; Mar. 22, s 

One turn of micrometer = 62.103". 

One division of level = 1.28". 

Total, 39 observations on 39 pairs. 

Latitude of Station No. 2 = 31° 47' 00.21" ■ 0.07". 

Latitude of Monnment No. 15, = 31° 47' 00.34". 

Latitude Station No. 2 was 4.1 meters soirtll and 5.3 meters wist of Monument 

The mean place, 1892, for star No. 400 as used in Uie latitude computation was 



■ 322 observed 16 • late ; Mar. 21, star 328 observed 1 
371 observed 20 " late ; Mar. 21, star 392 observed 
401 observed 4 " late. 



UNITED STATES AND MEXICAN BOUNDAKY. 
Station Xo. S, near Monument Xo. .'(!. 



77 



P 1341 
■ E.J. y , 

. Draconis J 



E. ,T. 41 ^l 
Leon.MinJi 



, E.J. a , 

I ITra. Miy.J 

Pfl37 



Microm- 


Level. 


Slar No. 


N.oi- 
S. 


Mieioni. 

eter 
reading. 


Le 

N. 


rel. 


Latitude, 
31° 46'. 


reiiin,. 


N. 


s. 


t. 


d. 


rf. 






'• 


d. 


.. 




17.491 


50.9 


18.0 


307 


S. 


22.681 


13.5 


46.2 


57.76 


:io. 632 


55.1 


22.1 


309 


s. 


9.670 


18.8 


52.0 


57.89 


30. 510 


19.9 


53.7 


313 


Jf. 


10. 842 


53.2 


19.2 


58.59 


)7.6,'i7 


16.5 


50.5 


315 


N. 


22. 391 


49.4 


15.1 


57.24 


24.9«0 


17.7 


51.9 


319 


N. 


15.465 


51.1 


16.9 


58.21 


8.817 


1.-1. 2 


50.0 


324 


N. 


31.387 


50.7 


15.9 


,50. 78 


28. IG 1 


55.2 


20.2 


328 


S. 


11.844 


19.8 


55.0 


57.71 


19.399 


51.2 


15.9 


330 


s. 


20. 128 


14.0 


50.0 


58.98 


22.069 


.51.7 


16.0 


334 


s. 


18.498 


15.0 


51.0 


57.82 


16.246 


49.2 


13.0 


340 


s. 


23. 242 


11.5 


48.0 


58.65 


9.612 


53.4 


16.9 


345 


s. 


30.213 


15.2 


52.0 


59.09 


24. 189 


50.1 


13.1 


349 


s. 


17.020 


12.1 


49.0 


57.98 


12.149 


10.9 


53.8 


355 


N. 


27. 720 


54.0 


17.0 


57.70 


12.661 


51.0 


13.5 


366 


S. 


25.720 


12.9 


50.1 


57.96 


21.919 


52.9 


15.0 


371 


s. 


18.190 


14.5 


.52.0 


57.70 


16.010 


.56.0 


18.3 


375 


s. 


24. 140 


17.9 


55.3 


58.05 


23.415 


51.8 


13.9 


380 


s. 


17. 251 


13.0 


50.9 


57.80 


12.091 


14.9 


53.4 


390 


N. 


28. 409 


54.7 


16.0 


.57, 76 


26.491 


15.0 


53.8 


393 


N. 


13.857 


54. 


15.5 


58.14 


15.490 


54.0 


15.3 


399 


S. 


26. 139 


15.0 


53.9 


57.75 


32. 139 


14.0 


53.0 


401 


N. 


7.288 


53.3 


14.8 


58.92 


19.391 


52.0 


13.0 


404 


S. 


21. 261 


12.1 


51.2 


67.43 


27.569 


13.8 


52.8 


400 


N. 


13.318 


52.9 


13.8 


67.47 


11.092 


9.8 


48.8 


409 


N. 


29.539 


49.0 


10.0 


57.22 


18.750 


13.5 


52.7 


414 


.V. 


21. 980 


52.9 


13.5 


57. 93 


24. 851 


12.1 


51.4 


417 


N. 


14.679 


52.0 


12.6 


58.59 


21.890 


11.0 


50.2 


421 


X. 


17.992 


50.9 


11.2 


58. 18 


29. 010 


66.1. 


16.9 


424 


s. 


11.518 


15.6 


55.1 


57.92 


14.911 


15.2 


5.5.0 


I" 1350 


N. 


24. .501 


54.9 


15.0 


.50.70 


32.091) 


55.1 


15.6 


J. A Ophin. 


S. 


8. .'592 


15.6 


,55.2 


54.77 


24. 192 


18.0 


51.5 


303 


N. 


15. 501 


48.0 


14.6 


58.27 


15. 748 


51.0 


17.1 


305 


S. 


25. 298 


17.9 


52.0 


57.00 


15. 501 


52.0 


17.0 


311 


S. 


22.251 


12.9 


48.0 


.58. 10 


2u.G:a 


12.9 


48.0 


I'963_ 


N. 


10. .582 


50.0 


14,0 


58.11 


31.108 


14.2 


51.0 


1-1004 


N. 


9.279 


511. 


14.0 


58. 38 


27. 742 


..-,.0 


52. 1 


, K. J. 2 ^ 
I Can. Ve.i. 1 


N. 


13. 512 


52.3 


15.2 


.58. 03 


18. 52(1 


46.9 


9.9 


1 E-J-y , 
IVivgii. (m)/ 


s. 


19. 908 


9.2 




58. 1(> 



20, 359 


52. 1 


.::\ 


28. 509 


.53.0 


10.8 


20. 911 


1...0 


51.5 



301 

P(5293) 

J. 4 2 ^ 

Loon.Min. J 

E.J. cr» > 

Clancri. (in)/j 



Apr. 8, star 329 observed 16" late. 

Apr. 12, star 295 observed 11 " late ; Apr. 12. star 21 

One turn of micrometer = 62.118". 

One division of level = 1.28". 

Total, 46 observations ou 46 pairs. 

Latitude of .Station No. 3 =31° 46' 58.00" ± 0.05". 

Latitude of Monumeut No. 26 = 31=> 46' 58.08". 

Latitiub^ Station No. 3 -svaa 2.5 meters south aud ,) 

The I1I0.-IU place, 1892, lor the star No. 400 as u3„d 



Monument No. 26. 



78 



UNITED STATES AND MEXICAN BOUNDARY. 



Sialion Xo. 4, intersection of parallel 31'^ 47' and iiiiridiaii, near Monn 



Microm- 
eter 
reading. 



Star 


N.orS. 


Microm. 

eter 
reading. 


Level. 


I/atitude 


No. 


N. 


s. 


31°4o" 






I. 


d. 


d. 




315 


N. 


22. 581 


52.0 


22.1 


59.11 


316 


N. 


22.442 


47.2 


13.0 


58.23 


31.5 


X. 


22. 490 


50.0 


17.0 


57.90 


313 


N. 


22.459 


49.1 


14.0 


58.47 


315 


N. 


22. 829 


54.0 


17.9 


68.59 


315 


N. 


22.470 


50.2 


17.0 


58.74 


315 


N. 


22.886 


54.1 


19.0 


58.08 


319 


N. 


15.258 


45.8 


15.0 


50.63 


310 


N. 


15.462 


43.0 


8.7 


56.17 


319 


N. 


15, 529 


55.4 


22.3 


58.79 


3in 


N. 


15. 852 


57.7 


22.0 


58.84 


319 


N. 


15.408 


53.1 


16.5 


59.14 


319 


N. 


13.410 


52.0 


18.0 


58.97 


319 


N. 


15. -,'•.4 


52.0 


10.1 


59.26 


324 


N. 


31.814 


50.1 


19.0 


59.09 


324 


N. 


32. 340 


51.2 


17.0 


58.64 


324 


N. 


31. 270 


51.8 


18.2 


58.64 


324 


N. 


31.683 


51.9 


15.4 


59.40 


324 


N. 


31. 273 


50.0 


13.0 


58.01 


324 


N. 


31.350 


50.9 


10.3 


58.50 


324 


N. 


32.093 


54.9 


18.0 


59.13 


328 


S. 


11.911 


13.0 


44.8 


57.31 


328 


S. 


11.943 


13.9 


47.9 


57.85 


328 


S. 


11.703 


12.9 


50.0 


58.07 


328 


S. 


12. 018 


14.4 


52.3 


58.80 


328 


s. 


11.091) 


10.3 


51.0 


58.37 


328 


s. 


11.800 


13.1 


51.0 


58.75 


■ 330 


s. 


20.086 


8.9 


40.0 


59.74 


330 


s. 


20.848 


11.9 


45.8 


59.44 


330 


s. 


21. 058 


23.8 


57.1 


58.77 


330 


s. 


20.505 


10.0 


47.2 


59.24 


330 


s. 


20. 018 


12.9 


50.8 


58.69 


33D 


s. 


20.931 


21.7 


50.2 


58.74 


330 


s. 


21.019 


10.4 


54.1 


58.41 


334 


s. 


18.202 


14.1 


40.0 


00.21 


334 


s. 


18. 185 


15.8 


49.1 


57.81 


334 


s. 


18. 421 


20.3 


54.0 


58.21 


334 


s. 


18. 233 


9.7 


47.7 


68.30 


334 


s. 


18. 499 


18.0 


50.7 


58.50 


334 


s. 


18. 572 


15.0 


50.1 


58.54 


334 


s. 


18.010 


15.0 


53.3 


58.32 


340 


s. 


23.492 


17.5 


49.6 


59.67 


340 


s. 


23.511 


17.0 


50.3 


58.49 


340 


s. 


23.051 


19.9 


53.8 


58.03 


340 


s. 


23. 242 


14.0 


63.0 


58.61 


340 


s. 


23. 141 


10.1 


55.1 


58.51 


340 


s. 


23.700 


14.0 


49.9 


58.71 


340 


s. 


23.540 


14.5 


63.5 


58.45 


3J5 


s. 


30. 035 


15.6 


48.0 


58.92 


345 


s. 


30.381 


12.8 


40.4 


58.81 


345 


s. 


29.908 


10.7 


50.2 


58.19 


345 


s. 


30. 032 


14.0 


52.8 


58.46 


345 


s. 


30. 203 


10.0 


49.0 


58.74 


345 


s 


30. 298 


14.0 


49.9 


58.62 


345 


,s. 


30. 539 


12.8 


51.9 


58.64 


349 


s. 


10.541 


21.7 


54.1 


64.48 


349 


s. 


16.385 


17.9 


62.0 


58.48 


349 


s. 


10.362 


1.3.1 


46.8 


58.66 


349 


s. 


10.509 


16.0 


55.0 


57.79 


349 


s. 


17. 059 


14.1 


53.3 


58.31 


349 


s. 


16. 520 


15.0 


51.0 


58.65 


349 


s. 


10. 439 


14.1 


53.4 


58.00 



1892. 
Apr. 18... 



18.031 
24.761 I 
24.941 ; 
25.070 
23.285 
24.919 i 
24.883 : 
23. 180 
9.180 
9.701 
8.690 
9.080 
8.660 
8.732 
9.471 
28. 259 
28. 319 
28. 107 
28.301 
28.071 
28. 239 
20. 040 
20. 172 
20.381 

19. 936 
19.970 

20. 300 
20.408 
21.852 
21.819 
22. 029 

21. 850 
22.119 

22. 222 
21.681 
16. 480 
16. 572 
10. 143 
10.313 
16. 227 
10. 800 
10.010 

9. 030 
10. 01(1 
9. G59 
9.090 
9. 904 
9.990 
10. 179 
23.735 



23. 579 
23. 820 

24. 300 
'23. 804 

23. 058 



19.6 
12.3 
25.0 
20.0 



52.7 
44.0 
47.5 
57.5 
50.3 
60.9 
57.7 
55.7 
'48.9 
50.2 
54.5 
48.0 
57.0 
51.5 '• 
55.4 



50.1 
51.2 
52.8 
47.0 
46.8 
51.0 
53.3 

SI 

51.0 
48.0 
52.8 
47.5 



54.0 j 
53.3 
52.6 



53.7 
50.2 
51.2 
49.2 



UNITED STATES AND MEXICAN BOUNDARY. 

fitatwn JVo. -i, hilersectioii of parallel Sl^ 47' and mendiaii, near Monument \o. */— Continued. 



1892. 
Apr. 18 



Microm 


Level. 


Star 
No. 












N-r 




X.orS 


reding 








reading 


s. 


N. 


1 s- 


-310 46'.*' 


(. 


d. 


d. 




j 


,. 


d. 


d. 


" 


12.735 


14. S 


47.3 


1 355 


1 N. 


28.331 


47.1 


14. 6 


i 58. 62 


12. 641 


16.0 


50.4 


355 


1 ^• 


28. 280 


51.4 


16.9 


58.38 


12. 150 


17.9 


51.3 


355 


N. 


27. 795 


52.0 


18.4 


58.14 


12. 100 




55.1 


1 355 


1 ^■ 


27.833 


56.3 


17.1 


58.72 


12.169 


! 15.5 


54.9 


I 335 


N. 


27. 810 


54.7 


15.5 


58.24 


12.429 


1 14.0 


50.1 


355 


N. 


28.060 


50.3 


13,9 


59. 05 


12.082 


15.0 


54.3 


355 


N. 


27.719 


53.3 


13.9 


58. 36 


18. 032 


50.8 


18,0 


! 362 


S. 


21. 980 


17.7 


.50. 8 




17. 880 


! 47.7 


12,9 


362 


S. 


21.821 


12.0 


47.0 


59.35 


18.000 


51.5 


17.9 


362 


s. 


21, 939 


17.0 


50.8 


59.43 


17. 839 


511. r 


11.0 


362 


s. 


21.732 


1 9.5 


49.0 


58.05 


18.140 


54.0 


14.7 


302 


•S. 


22. 069 


14.0 




59.27 


18. 240 


j 52.3 


i 15.3 


362 


s. 


22. 174 


15,0 


52.2 


59.57 


18.030 


54.0 


14.5 


362 


s. 


21. 952 


14.3 


54.4 


59.19 


12. 850 


51.1 


18.1 


366 


s. 


25.890 


17.8 


50.9 


58.38 


13.259 


52.1 


17.0 


366 


s. 


26. 267 


15.7 


50.6 


58.36 


12.080 


52.8 


18.8 


366 


s. 


26, 106 


16.9 


50.9 


59.38 


13. 289 


■ 54.7 


j 14.9 


366 


s. 


25.295 


12.9 


52.8 


58.93 


13. 262 


53.8 


1 13.9 


366 


s. 


26. 292 


13.5 


53.2 


58.91 


13.334 


54.0 


16.9 


366 


s. 


26, 348 


16.5 


54.0 


j 58.50 


13.354 


50.0 


19,0 


366 


s. 


26. 365 


18,9 


49.9 


58.55 


21. 672 


, 53.2 


18,8 


371 


s. 


17. 927 


17.9 


51.0 


58.88 


21.509 


50.1 


15.0 


1 371 


s. 


17.751 


14.0 


49.0 


58. 70 


21.558 


53.8 


19.2 


371 


s. 


17,788 


18.0 


52.4 


58.64 


21.923 


50.0 


16.0 


371 


s. 


18. 139 


13.5 


53.5 


59.13 


21.192 


55.1 


15.2 


371 


s. 


17.419 


14.5 


.54.1 


58.57 


21.507 


55.0 


17.9 


371 


s. 


17. 789 


17.9 


55.0 


58.21 


22.010 


43.4 


12.1 


371 


s. 


18.231 


12.0 


43.1 


58.30 


15.760 


47.1 


14.0 


375 


s. 


23.839 


13.5 


46.8 


58.27 


15.842 


50.2 


15.2 


375 


8. 


23.910 


14.7 


49.8 


58.29 


15.830 


53.2 


19.0 


375 


s. 


23. 889 


16.9 


51.0 


59.31 


16.050 


.12.1 


12.1 


375 


s. 


24.110 


13.0 


53.1 


57.54 


15. 693 


54.9 


14.9 


975 


s. 


23.728 


14.0 


54.0 


58.19 


15.870 


53.3 


16.0 


375 


s. 


23.929 


17.0 


54,1 


58.21 


15. 909 


52.0 


20.7 


375 


s. 


23.940 


20.9 


52.2 


58.02 


23.545 


46.0 


12.8 


380 


s. 


17.363 


12.2 


45.8 


58.93 


23. 609 


49.0 


14.0 


380 


s. 


17.382 


12.1 


47.0 


,58.47 


23.245 


.52.2 


17.9 


380 


s. 


17.050 


19.0 


53.2 


57.94 


22. 751 


53.3 


,3.1 


380 


s. 


16.550 


12.8 


53,0 


58. 79 


23.091 


.53. 


13.0 


380 


s. 


16. 849 


11.9 


52.0 


58.21 


22. 960 


.55.5 


18.2 


380 


.s. 


16. 720 


17.9 


35.2 


.58.23 


23. 216 


47.0 


15.0 


380 


s. 


16. 978 


15.1 


46.9 


58.52 


15. 050 


47.3 


13,9 


386 


s. 


25. 750 


12,3 


46.0 


58,30 


14.819 


51.2 


15 5 


386 


s.. 


25.505 


13.9 


49.8 


58.24 


14. 700 


48.8 


U.3 


386 


s. 


25.429 


16.5 


49.9 


58.07 


14.449 


54.0 


13.2 


386 


s. 


25. 160 


13.0 


54.0 


58.51 


14.685 


54.0 


13.5 


386 


s. 


25.351 




52.0 


58.40 


14. 770 


.55.0 


17.6 


386 


s. 


25.450 


17.0 


54.8 


58.43 


14. 641 


50.2 


19.0 


386 


s. 


25. 345 


18.2 


49.0 


59.59 


11.669 


16.0 


49.9 


390 


N. 


28.019 


50,3- 


16.8 


58.48 


12.2.50 


12.0 


47.9 


390 


N. 


28. 630 


49.1 ! 


1.3.1 


58.20 , 


11.991 


10. 9 


51.5 


390 


N. 


28.332 


51). 2 


15.5 


58.6 


12.039 ) 


13.0 


54.0 


390 


N. 


28.391 


53.7 


12.8 


58.64 


12. 220 


1.5.5 


56.0 


390 


N. 


28.639 


57, 2 [ 


16.8 


57.75 


12. 193 


18.9 


.56.4 


390 


N. 


28. 602 


57 6 


20.0 


58.47 


12.229 


16.0 


47.1 


390 


N. 


28. 600 


46.9 


15.0 


58.96 




13.3 


47.2 


393 


N. 


13.435 


48.9 


15.0 


58.14 


26. 040 


20.0 


55. 


393 , 


N. 


13. 439 


54.8 


20.0 


59.26 


26. 261 


12.4 


53.3 


393 


N. 


13. 700 


53.5 


12.0 


58.42 


20.421 


15.0 


55.8 


393 


N. 


13.890 


57.1 


10.3 


58.42 


20,241 


15.9 


53.3 


393 


N. 


13. 700 


53.4 


16.0 


58.42 


20.560 


17.5 


48.8 


393 


N. 


14.000 


47.6 


10.7 


58,55 


9 observ 


a 21' la 


<■.: Apr. 


20, 8t,ar a 


23 obsei 


ve<l 5- late 









80 



UNITED STATES AND MEXICAN BOUNDARY. 
Station Xo. 4, intersection of parallel 31^ 47' and meridian, near Moiinment Xo. •/(?— Continued 




One turn of micrometer = 02.105". 

One division of level = 1.28". 

Total, 130 observations on 19 pairs. 

Latitude of Station No. 4 = 31° 46' 58.65" i O.fl 

Latitude of Monument No. 40 = ;ilo 46' 59.72". 

Latitude Station No. 4 was 35.9 meters soutli and i 

All paira were given equal weight. 



Station No. n, intersection of imrallel Sl° 20' and meridian. 



eading. 


N. 


t. 


d. 


20. 160 


15.6 


25. 987 


20.0 


19. 159 


52.2 


18.761 


51.0 


30. 018 


52.8 


30.532 


54.3 


27. 759 


19.2 


28.117 


13.8 


18. 832 


16.4 


18.812 


15.6 


28. 998 


14.0 


27.767 


15.0 


32. 420 


14.8 


32.078 


15.6 


21.251 


52.8 



31.314 
28. 969 
28.437 



18.758 
16.669 I 
17. 059 



^Z. 7 ] 
53. 6 j 



378 I 
■378 i 



S. ; 26. 540 



22. 458 


53.4 


23. 151 


56.1 


26. 377 


15.9 


20. 523 


15.0 


20.927 


14.6 1 


26. 540 


1.5.0 



8.692 


50.0 


15.1 




9. 022 


55.7 


14.8 




24. 019 


14.1 


5.5.2 




23.642 


11.6 


55.5 




7.563 


54.3 


13.2 




8.300 


54.0 


13.0 


14.341 


13.9 


56.0 


14. 142 


14.0 


55.5, 


26. 850 


55.0 


13.1 1 


M 


iy27,st 


r 394 ob 


served 



14.239 
22.441 
22.011 



21.550 
21.530 
12.305 
10.911 
8.136 
7.791 
16. 850 
16.581 
9.251 
10. 309 
12. 322 
11.601 
10.499 
10.298 
19. 334 
19.485 
22. 038 
21.639 
23. 409 
23. 802 
12.568 
12. 391 



14.142 
IS. 770 
30. 560 
30. 878 
15. 940 
15. 583 
32.018 
32.716 
26. 807 
26. 632 
13. 128 



Level. 1 


- 


S. 


d. 


d. 


48.2 


14.0 


54.!) 


19.0 


16.1 


52.7 


14.2 


50.7 


16.5 


.53.2 


17.1 


64.1 


55.1 


16.1 


52.8 


15.0 


53.1 


16.0 


54.0 


15.8 


61.2 


14.0 


45.8 


7.2 


51.7 


14.0 


54.0 


15.0 


14.9 


52.4 


14.9 


53.5 


52.7 


14.6 


55.0 


10.0 


50.2 


12.1 


54.9 


15.6 


16.9 


55.1 


1.5. 


54.9 


55.9 


17.1 


55.3 


15.4 


04.0 


15.0 


55.0 


14.9 


16.1 


55.5 


13.2 


53.7 


51.6 


11.9 


55.6 


15.0 


13.0 


63.0 


14.0 


.54.9 


56.1 


15.9 


57.0 


16.1 


55.1 


14.2 


56.2 


15.5 


15.2 


56.1 


14.0 


55.0 


55.9 


14.9 


56.6 


15.5 


12.1 


53.7 


12.0 


53.0 


50.1 


14.2 


57.3 


15.7 


12.5 


5-1.8 



2.00 
2.16 
2.70 
2.46 



2.37 
1.96 
1.15 
2.56 



UNITED STATES AND MEXICAN BOUNDARY. 
station No. 5, intersection of parallclJi M' and mcn'rfiaH— Continued. 



81 



1892. 
May 27.. 



V Lyra. 
E.J. 

V Lyric. 



429 ' S. 



26. 974 
21. 73fl 
22. 150 

28. 370 
28.552 
29. 810 

29. 691 
25. 852 
20. 030 



27.011 


.■55.2 


27. 070 


50.0 


28. 261 


55.2 


28. 481 


50.9 


13.590 


13.0 


13. 449 


18.9 


29. 100 


12.8 


28.870 


18.2 


21.660 


.53.1 


21. 828 


53.2 


28.231 


56.0 


27. 801 


51.3 


11.974 


50.2 


11.730 


52.; 


29 893 


54.2 


29 0I!2 


52.2 



11.549 


10.9 


.')2.2 


12. 702 


15.0 


52.2 


12. 5o0 


17.9 


56.0 


23. 710 


.16. 1 


11.2 


23. 750 


50. 1 


14.6 


20. 008 


16.5 


54.0 



10.818 


52.0 


16.4 


18. 670 


57.8 


12.0 


18.301 


51.8 


16. 


14.461 


52.0 


14.0 


15.002 


53.4 


15.3 


24.3.55 


50.7 


11.0 


24.888 


54.0 


18.0 



13.222 
18. 330 
18. 739 



U. 079 


54.8 


11.8 


2.07 


14. 702 


12.5 


56.0 


1 14 


14.895 


13.0 


55.9 


I.. 39 


30.999 


56.8 


13.2 


1.01 


30. 693 


57.9 


14.7 


1.05 


19.490 


12.5 


55.5 


1.99 


12. 548 


11.1 


54.2 


2.42 


12.655 


17.8 


52.0 


2.46 


11. 261 


11.0 


54.2 


2 18 


n.507 


17.4 


52.1 


2.02 


26. 041 


57.4 


14.2 


1.97 


25.869 


52.0 


17.0 


1.31 


11.590 


56.7 


13.6 


2.66 


11.335 


51.9 


16.3 


2.35 


17.394 


18.8 


54.0 


1.91 


11541 


17.8 


53.8 


1.66 


12.499 


11.0 


55.0 


2.03 


12.091 


16.7 


52.0 


2.82 


28.719 


12.0 


56.0 


2.25 


2-i. 481 


18.5 


54.0 


2.18 


11.436 


20.0 


55.6 


1.96 


11.168 


10.0 


52.7 


1.65 


£0.071 


9.9 


54.3 


2.47 


25.920 


17.5 


52.8 


2.06 


28.920 


59.2 


14.5 


1.82 


28.959 


51.0 


15.1 


1.30 


26.991 


50.9 


13.1 


1.80 


26. 791 


.57.2 


19.2 


1.91 


15.875 


11. 


56.0 


2. o:i 


15.912 


16.4 


52.0 


1.10 


20. 329 


53.2 


15.8 


1.72 


20. 163 


52.8 


15.0 


2.36 


11.453 


12.1 


57.7 


1.67 


11.512 


16.3 


52.0 


2.:'.9 


22. 770 


11.3 


57.0 


2.06 


23.411 


17.9 


53.5 


2 32 


21. 799 


11.5 


57.0 


:;.39 


21.455 


17.0 


53.0 


2.56 


25. 729 


15.0 


53.0 


2.11 


20.260 


16.8 


54.9 


1.70 


14. 659 


10.9 


50.4 


2.88 


15. 182 


19.0 


55.1- 


2.30 


14.400 


17.2 


55.9 


2.17 



■{<-AquU.}| 



May 26, star 430 observed 15 • late: May 27, star 434 i 
One turn of micrometer = 62.093". 
One division of level = 1.28". 
Total, 99 observations on 50 pairs. 
Latidideof Station Uo. 5 = 31^20' 02.00" 0.04". 
Latitude of Monument No. 53 = 3.= 20' 01.79". 
Latitude Station No. 5 was 6.4 meters north and 4.4 i 
Ail pairs were given iqual weight. 



t of Monumaut No. 53. 



82 



UNITED STATES AND MEXICAN BOUNDARY. 



]fliitewater Sj)7'ing. 



Microm- 


Le\ 


r^X,. 


N. 


t. 




33.415 


18.2 1 


24. 820 




24.370 


51 2 


JO. 650 


10.8 1 


30.602 


17.9 ! 


2&a38 


16.6 1 


29.230 


.0..! 



20.675 


16.0 


50.3 


18.152 


19.0 


55,0 


18.470 


18.1 


53.0 


17.358 


54.9 


19.0 


17.871 


51.2 


16.0 


27. 949 


17.5 


54.0 



H Jnne 10, star 



26.723 


18.1 


55.6 


26. 731 


16.9 


53.0 


8.838 


55.0 


17.0 


9.341 


53.5 


16.8 


23. 879 


1.5.9 


54.0 


24. 551 


16.0 


53.0 


8.110 


52.7 


14.8 


8. 248 


.52.8 


15.7 


14.201 


16.8 


55.3 


14. 120 


14.3 


52.0 


27. 198 


52.0 


13.2 


26.870 


53.1 


15.6 


21.449 


14.9 


53.9 


21.194 


15.9 


53.4 


27. 809 


15.0 


54.2 


28. 160 


15.2 


53.3 


29.630 


14.2 


53.4 


29. 519 


18.0 


56.2 


25.958 


54.0 


15.0 


25.411 


.52.3 


14.0 


9. .570 


16.2 


55.8 


9.702 


15.0 


54.1 


19.999 


51.2 


11.9 


20.251 


54.2 


15.5 


18.073 


55.0 


15.5 


18. 958 


,15.1 


16.3 


28. 735 


54.9 


15.0 


28.795 


55.2 


16.3 


13. 790 


14.0 


54.2 


13.316 


15.0 


53.8 


28. 741 


14.1 


54.9 


29.441 


16.0 


54.4 


22. 144 


5,5.0 


14.2 


22.490 


53.0 


15.7 


27.810 


52.5 


11.8 


27.640 


52.2 


14.0 


11.901 


56.4 


15.7 


12.370 


54.9 


16.5 


29.579 


54.5 


13.5 


29.380 


52.3 


U.O 


13.117 


54.0 


12.8 


r 423 (lb 


seiveil 1 


2- Late; 



Microm- 
reading. 



8.393 
17. 174 
16.781 
9.811 
9.802 



12.782 I 
10.320 
10.340 
19.201 
19. 480 
21.418 
21. 772 
23.918 
24.420 I 
12.261 
12.505 



30.516 
31.000 
16.076 
16.712 
32. 289 
32. 409 
26.911 
26. 851 
13.240 
12.911 
18. 280 
18. 050 
11.915 
12. 170 



.291 



14.9 
19.3 
49.3 
49.3 j 
50.9 
S3.0 
14. s' 
15.0 i 
53.4 



55.0 
57.0 
13.3 
12.9 





57.7 


31. 409 


.55.3 


19. 188 


10.0 


19.458 


14.8 


22.599 


14.0 ' 


23.489 


15.3 


11.420 


13.2 


11.490 


15.2 


26.520 


56.0 


26.061 


55.0 


11.519 


50.2 


12.240 


54.8 


17. 478 


8.8 


17.890 


U.l 


11.878 


14.0 I 


11.606 


12.8 


28. 370 


16.0 


28.781 


15.0 


10. 825 


13.9 


10.579 


12.3 


26. 318 


13.2 



50.3 


10.0 


55.7 


19.8 


55.0 


20.0 


18.0 


54.2 


15.1 


50.3 


54.2 


17.9 


53.3 


17.7 


15.7 


52.8 


15.9 


51.9 



17.8 
15.8 
50.2 
53.0 
17.0 
14.4 
51.1 
53.1 
15.0 
16.0 
16.0 
15.0 
15.8 
18.9 
52.8 
51.2 
18.0 
16.8 
49.3 
53.2 



58.06 
58.13 
57.76 
58.65 
58.17 
58.30 
58.54 
57.95 
57.94 
57.71 
57.90 
58.24 
58.13 
58.21 
58.17 
58.44 
58.34 
57.85 



57.51 
58.06 
57.31 
58.67 
57.85 
57.99 
58.79 
58.67 



57.64 
57.30 
58.45 
57.85 
58.00 
58.45 
.58.50 
59.00 
57.49 
57.61 
57.37 
57.20 



58.08 
58.40 
57.25 
57.63 
58.05 
57.80 
58.80 
57.93 
57.61 
57.46 
58.50 
58.00 
58.17 
58.17 
57.18 
57. *3 
58.17 



1 14, star 430 nliserved 18' late. 



UNITED STATES AND MEXICAN BOUNDAEY. 
Station Xo. 6, near Whitewater .S^Hni;— Continued. 



Microm- 
eter, 
reading. 



83 



484 


S. 
N. 


485 


.S. 


480 


s. 


489 


s. 


494 


s. 


494 


s. 


P. 1775 


s. 


P. 1775 


s. 


Grooms 


Jf 


3241 1 




Groom > 


N 


S241 1 




J. > 


N. 



E.J. 

a CeplK 



20. 963 
20. 645 



10. 319 


13.5 


53.3 


3D. 8211 


13.8 


56.1 


31. 338 


l.'i. 


54.9 


10.834 


15.0 


57.5 


11.176 


13.2 


55.0 


29.827 


.50.2 


13.9 


20.959 


14.9 


54.8 


14. 190 


13.4 


58.2 


14. 943 


13.3 


53. C 


21.948 


13.0 


55.9 


22.318 


14.8 


5.5.0 


9.230 


12.0 


55.0 


8.819 


14.8 


55.0 


22.821 


55.9 


12.9 



26.340 
29.361 
29.511 



11.679 
23.099 I 
23.011 : 
21.437 I 
25.580 



;.9n9 



17.945 
17.281 I 
29.070 
28.979 
9.030 



1.490 



18.763 
25. 175 
25. 880 
16. 063 
18.379 
31.799 
31.379 
16.585 



53.0 
58.5 
14.0 
16.0 
11.0 



53.3 
13.0 
53.6 
57.0 
52.0 
57.0 



13.5 
15.2 
13.8 ■ 
55.8 
13.5 
14.0 



53.8 
55.3 



57.52 
57.77 
58.11 
57.41 
57.12 
58.48 
58.16 
58.17 
58.41 
57.93 
57.91 
58.04 
58.45 
58.11 

57. I9 
57.15 
57.95 
57.89 
56.95 
57.56 

58. U3 
57.90 
57.37 
.57.74 
57.73 



57.81 
58.08 



1, r. . 

\( Herculisi 



|l Herculisi 

16.8 ' 50.2 / •'^■G™o"> I 

I 2343 /I 

17.8 ' 51.9 P. 1513 



58.70 
57.29 



,1 *■" ! 
One turn of micrometer ^= 62.101". 
One division of level = 1.28". 
Total, 102 observations on 57 pairs. 
Latitnde of Station No. = 31° 19' 57.94" 
Tbere was no monument near the station 
Weight of pairs on which two observatio 



84 



TTNITED STATKS AND MEXICAN BOrNDARY. 



yo. 7, S miles west of San Lids . 



Muiiiniieiit No. 67 



Star So. 


V 


Microni' 
11.571 


452 


», 


J52 


s. 


18.842 


391 


N. 


9.060 


395 


S. 


24.668 


398 


N. 


8.154 


402 


S. 


U. 451 


402 


S. 


13. 021 


408 


N. 


28.368 


412 


S. 


22.600 


412 


s. 


20.549 


416 


s. 


29.240 


410 


s. 


27.728 


420 


s. 


30. 248 


420 


s. 


29.510 


425 


s. 


24.649 


425 


s. 


23.670 


427 


N. 


26.696 


427 


N. 


25. 589 


420 


s. 


10. 941 


431 


N. 


21. 791 


431 


N. 


19. 991 


433 


X. 


19. 610 


433 


N. 


18.827 


436 


N. 


29.591 


430 


N. 


28.340 


438 


S. 


14. 500 


438 


s. 


13.080 


440 


s. 


29. 780 


440 


s. 


27.908 i 


442 


N. 


24.472 


442 


N. 


22.062 


444 


N. 


29. 108 


444 


N. 


27.998 


446 


N. 


13.071 


440 


N. 


11.955 


448 


X. 


31. 106 


443 


N. 


29.686 


450 


N. 


14.381 


450 


N. 


13.382 


456 


N. 


19. 573 i 


489 




14. 789 


489 


s. 


14.559 t 


494 


s. 


21.791 


494 


s. 


21.491 


P. 1776 


s. 


8. .348 


E. Grooin^ 


. 


... 



57.6 


498 


53.8 


P. 1783 




/ B- 1 




{^Aanarul 




I 1 Pegasi 1 






, E..I. , 


..4 U 


^ 1 1 Ceiilici / 



n,li. '! N- ! 



P. 1513 


N. 


P. 1513 


N. 


455 


N. 


455 


N. 


400 


N. 


4M 


■■^- 



N.or 


Microm. 

eter 
reaxling. 


Level. 


Latitude, 




X. 


s. 


31° 19'. 


N. 


29.479 


d. 
54.1 


16.9 


" 
56.68 


N. 


29. 781 


52.2 


20.0 


56.35 


S. 


31.252 


11.4 


41.1 


55.82 


N. 


16.992 


50.1 


20.0 


56.94 


S. 


32.168 


19.3 


60.1 


55. 6« 


N. 


27.403 


56.1 


24.0 


56.17 


N. 


25.940 


49.8 


17.9 


57.25 


S. 


14.279 


20.0 


52.3 


55.99 


N. 


19. 562 


49.3 


17.0 


57.36 


K. 


17.646 


52.7 


20.9 


56.80 


K. 


13.409 


51.7 


19.0 


56.97 


N. 


11.968 


61.8 


17.0 


50.64 


N. 


11.980 


47.0 


14.7 


.57.49 


K. 


11.389 


51.6 


18.9 


57.34 


N. 


18. 203 


53.7 


20.8 


57.66 


X. 


17.261 


51.1 


15.3 


57.01 


S. 


15.114 


18.9 


51.7 


57.08 


S. 


13.939 


17.9 


53.9 


56.54 


X. 


32. 810 


52.0 


19.3 


56.14 


s. 


20.848 


18.5 


50.8 


.56.85 


s. 


19. 029 


17.9 


51.0 


57.21 


s. 


23. 940 


20.8 


.53.0 


56.33 


s. 


23. 131 


15.3 


49.8 


57.06 


s. 


12. 089 


18.9 


.51.0 


66.84 


s. 


10. 851 


17.0 


.52.2 


56.86 


X. 


27. 456 


52.0 


19.8 


56.41 


N. 


26. 128 


54.0 


20.1 


57.39 


X. 


12.761 


53.3 


21.2 


57.96 


X. 


10.991 


54.3 


14.2 


56.20 


s. 


19. 679 


20.2 


52.3 


56.26 


s. 


17. 769 


14.0 


54.0 


56.61 


s. 


12. 889 


18.4 


50.4 


56.98 


s. 


11. 670 


12.0 


52.3 


50.95 


.s. 


29.314 


18.0 


49.9 


57. .57 


s. 


28.173 


18.3 


54.2 


57.28 


.s. 


12. 159 


24.3 


56.2 


56.34 


s. 


10.648 


13.9 


49.8 


.56. 61 


s. 


27. 349 


19.3 


51.7 


56.23 


s. 


26.270 


13.5 


53.2 


56.96 


s. 


22.499 


19.2 


51.7 


.56.74 


X. 


26.010 


52.3 


18.9 


56.82 


X. 


25.902 


56.1 


11.3 


57.13 ! 


X. 


18. 150 


53.1 


18.2 


.57. 17 


X. 


17.991 


57.0 


11.5 


.57.27 


X. ! 


31.230 


56.3 


20.8 


.56.46 


s. 


16. 682 


14.9 


.■52.3 


56.49 



2.5.911 


51.2 


20. 599 


50.9 


15.410 


5.5. 8 


12. 888 


.i4. 2 


27.820 


52.0 


26.791 


50.0 


19. 992 


53.7 


22.700 


14.9 



.55. 46 
.57. 15 



July 27, star 402, obsci 



ITNITEI) STATES AND MEXICAN BOUNDARY, 
T. 3 miles ivrst uf San Li(h Sj)iinfj, near Monument jV'o. o; 

Level. I [ „ I Mirrnn, 



1892. 

July 26 . 



■iSerpenlis' 

E.J. > 

iSerpentis' 



reading. 



27. 14U 


54.4 


26. 368 


53.3 


13.800 


10.2 


13. 959 


14.2 


24. 072 


53.2 


24. 369 


56.1 



15. 678 


57.0 


.■1.808 


55.0 


22.508 


14.9 


10. 599 


15.0 


11.001 


15.0 


7.852 


57.0 


7. 728 


.18.3 



Star No. 



reading. 



7.9 


55.0 


5.0 


50.2 


5.6 


53.2 



Level. ! 
Latitude, 

: I c I 30° 19'. 1 



19.9 54.0, 

U. 121 ' 50. 1 24. 



21. 520 


19.1 


54.2 


57.60 


15.402 


17.2 


52.2 


57.41 


13. 989 


16.9 


.54.2 


.56. 73 


13. 820 


15.9 


.56.7 


.56.80 


20.842 


54.2 


10.7 


.--,6.29 


27.009 


55.0 


14.0 


55.91 


16.918 


15.2 


53.0 


56.51 


17.223 


15.0 


56.0 


56.74 


26.612 


54.0 


16.1 


56.49 


26.921 


55.9 


14.9 


56.87 


22.i)75 


55.8 


17.9 


56.88 


22.741 


57.5 


16.2 


56.85 


28. 996 


55.8 


18.0 


56.06 


29.469 


56.9 


15.6 


56.44 


9.863 


53.4 


15.9 


56.62 


9.891 


56.3 


15.0 


57.08 


27. 689 


15.5 


53.2 


56.55 


28.280 


U.2 


56.2 


50.54 


11.935 


54.5 


16.7 


56.93 


11.979 


58.0 


15.7 


57.28 



25. 740 
26. 318 
27.522 ; 



15. 753 
311. 338 



55.0 


56. 62 


59.4 


56.64 


54. 1 


56.31 


16. n 


56.86 


16.8 


56.25 


10.0 


56.85 


55. U 


56.89 


.59.2 


56.84 


10.8 


r<i. 17 


15.0 


50.09 


15.2 


57.36 


56.2 


56.80 



July 20, star P. 1358 observed 12' late. 
One turn of niicronietcr = 62.078". 
One division of level = 1.28". 
Total, 99 observations on 63 j>airs. 
Latitude of Station No. 7—31^ 19' 56.73' ± O.O 
Latitude of Alonuiucnt No. 67 =31'^ 19' 50.80" 
Latitude of Station No. 7 was 4.1 meters son; 
Weight for pairs on which two observations 



H6 



UNITED STATES AND MEXICAN BOUNDARY. 
Slation No. S, San liernardino lianch, Arizona. 



Microm- 
roading. 



s. 


22. 820 


19.0 


54 9 


N. 


24. 712 


52.9 


17.9 


N. 


30. 290 


52. 5 1 


17.6 


.S. 


19.327 


18.1 


53.4 


s. 


15.059 


19.0 


54.0 


s. 


19.510 


17.2 


62.8 


s. 


28.183 


16.9 


52.4 


s. 


29. 358 


12.9 


57.6 


N. 


27. 160 


54.0 


18.1 


X. 


21. 870 


54.8 


18.3 


X. 


16.611 


.54.0 


17.1 


N. 


21 221 


53.0 


15.8 


if. 


29.039 


53.9 


10.5 


S. 


15.032 


■14.9 


52.3 


s. 


21.630 


15.7 


53.3 


N. 


30. 139 


52.8 


14.9 


X. 


20.491 


61.1 


20.0 


N. 


19.966 


.50.1 


17.1 


N. 


18. 152 


52.5 


20.9 


X. 


18.052 


.53.1 


19.1 


N. 


29.098 


52.2 


19.6 


N. 


29.690 


53.3 


18.3 


S. 


13.676 


16.3 


.50.0 


s. 


14.010 


17.0 


53.1 


s. 


28.901 


24.0 


68.0 


s. 


28. 881 


18.5 


55.0 


N. 


23.280 


52.6 


18.1 


K. 


23. 058 


53.0 


16.2 


N, 


28.621 


53.9 


19.0 


N. 


28. 790 


52.1 


15.0 


N. 


12.950 


52.8 


17.9 


N. 


12 864 


54.2 


17.0 


N. 


.30.236 


51.9 


16.9 


N. 


30.308 


53.0 


15.4 


X. 


13.570 


54.9 


19.0 


N. 


13. 709 


53.0 


15.0 


S. 


11.097 


16.3 


53.3 


X. 


19. 049 


54.0 


16.2 


N. 


18.900 


56.3 


12.0 


N. 


28.002 


65.4 


17.5 


N. 


28.680 


57.9 


13.2 


N. 


17. 180 


54.1 


15.6 


N. 


17. 033 


53.0 


13.9 


N. 


19.219 


54.2 


15.3 


S. 


32.609 


20.7 


54.3 


N. 


23.470 


51.9 


17.8 


N. 


26.755 


51.7 


17.3 


S. 


14.079 


1 18.6 


52.8 



16.5 


52.0 


53. 8 


18.3 


16.8 


62,0 


14.7 


58.7 


53.0 


17.1 



Microiii- 
reading. 



f- 


10.259 


57.6 


13.8 


59.62 


^. 


16. 989 


56.0 


20.9 


58.99 




13. 68'J 


!7.9 


52 8 


58.72 




9. 130 


16.4 


51.7 


58.78 


^. 


19.915 


54.2 


19.0 


59.08 


f. 


26.829 


,56.2 


21.0 


59.65 


^. 


18.782 


53.3 


17.8 


58.97 




10. 004 


52.8 


16.9 


68.76 




11.230 


58.0 


13.0 


68.93 


<. 


11.599 


17.9 


53.9 


58.70 


^. 


17.859 


17.4 


54.1 


58.32 


^, 


21.940 


17.1 


54.0 


69.38 


s. 


17.420 


15.4 


52.8 


59.44 


5, 


9.800 


16.0 


53.4 


59.03 


v. 


22.980 


52.9 


15.0 


59.48 


S'. 


16. 990 


54,0 


16.1 


59.36 


s. 


8.291 


14.0 


52.0 


59,28 


s. 


19.501 


19.1 


50.7 


58.92 


s. 


18.982 


18.0 


51.3 


58.07 


s. 


22.391 


19.0 


51.6 


59,19 


s. 


22.330 


18.7 


53,2 


59.68 


s. 


11.479 


17.7 


50.9 


59.03 


s. 


12.092 


18.0 


53.4 


58.82 


N. 


26.758 


.52.7 


19.0 


69.32 


N. 


27. 070 


54.0 


17.9 


58.96 


N. 


11.961 


55.9 


21.7 


59.71 


X. 


11.992 


55 


18.3 


59.60 


s. 


18. 368 


17.9 


52.2 


58.55 


s. 


18. 121 


15.4 


52.2 


58.21 


s. 


12. 304 


17.9 


52.6 


59.79 


s. 


12.480 


14.2 


51.3 


59.86 


s. 


29.011 


16.9 


51.9 


59.10 


s. 


28.928 


16.0 


53.5 


59. 26 


s. 


11.080 


16.0 


51.4 


57. 9G 


s. 


11.160 


13.8 


51.4 


58.91 


s. 


26. 440 


17.0 


53.2 


59.23 


s. 


26.57K 


13.2 


51.7 


59.23 


X. 


29.200 


5.5.1 


17.9 


58.59 


s. 


21.77P 


14.8 


52.7 


58.87 


s. 


21. 638 


12.0 


56.3 


58.97 


s. 


10.796 


15.0 


53.3 


58.78 


s. 


11.450 


13.5 


58.0 


58.68 


s. 


23.049 


14.0 


52.8 


58.84 


s. 


22. 962 


15.5 


55.0 


58.79 


s. 


21. 579 


13.8 


53.0 


59.05 


N. 


8.818 


52.0 


' 18.0 


58.89 


s. 


15.981 


19.0 


53.3 


58.66 


s. 


13. 530 


16.7 


52.9 


58.50 


X. 


27. 190 


52.7 


18.3 


68.78 


X. 


22. 959 


52.0 


17.2 


59.19 


N. 


13.561 


52.2 


17.3 


58.89 


X. 


13.796 


' 58.1 


16.0 


1 58.80 


N. 


22. 159 


52.3 


1 17.2 


58.08 


X. 


22.432 


56.1 


12.9 


58 90 


s. 


29. 964 


19. e 


54.2 


59.08 


X. 


27. 034 


] 51.9 


16.6 


5e.98 


s. 


12.362 


18.9 


54.1 


58.69 


X. 


12. 342 


1 63.0 


17.8 


59.71 


X. 


12. 575 


j 68.9 


14.9 


58.79 


s. 


11.570 


18.0 


54.0 


58.26 



■ 599 iibserved 15- lati; 



■ 460 observed 32" late ; Aug. 16, star 451 observed 7" lato. 



UNITED STATES AND MEXICAN BOUNDARY. 

Station Xo. S, San Brrnardino Ranch, Arizona— ConVmaii 



87 



reading. 



24.570 
14.445 
2U.425 
10. !>90 
14. 732 
14. 820 
28. 120 
10. 925 
11.518 
18.240 
32. 350 
32.182 



15.0 

54.0 ! 
56.3 

53.1 1 
15.7 



19.9GC 


17.0 


15.611 


56.7 


15. 740 


57.3 


14. 228 


56.2 


14.058 


58.0 


22. 921 


15.0 


22.761 


12.5 


10.056 


54.2 


18.080 


55.5 



12.2 
10. 

53.0 . 
56.6 I 

53.1 I 
53.3 [ 
S.5.5 



Aug. 16, star 592 observed 8- late. 

One turn of micrometer = 62.099 ". 

One division of level = 1.28 ". 

Total, 100 observations on 75 pairs. 

Latitude of Station No. 8 = 31° 19' 59.01 " ±4.03". 

Latitude of Monument No. 77 = 31° 19' 58.99". 

Latitude of Station Xo. 8 -n-as 0.7 meter north and 23.8 mi 

Weight for pairs on which two observations were made, 



Microm- 
, eter 
reading. 



15.845 


54.6 


18.9 


59.98 


26. 651 


54.1 


18.1 


59. 02 


21. 240 


31.1 


15.0 


58. 62 


24.502 


,52. 7 


16.0 


58.68 


25. 009 


16.4 


53.1 


58.94 


25. 650 


11.0 


55.5 


58.87 


n.53U 


52.0 


14.8 


58. 91 


2S. 753 


17.0 


54.2 


1 58.84 


29.338 


12.0 


56.2 


59. 07 


21.461 


16.0 


53.2 


59.10 


9.400 


52.8 


15.3 


68.82 


9.249 


56.3 


11.8 


58.62 


j 25.461 


53.0 


15.9 


58.77 


27. 393 


55.0 


16.5 


59.08 


20. 952 


57.5 


19.0 


59.77 


26. 190 


19.9 


59.5 


58.73 


26.254 


12.1 


57.0 


58.98 


27. 819 


15.0 


55.8 


58.49 


27. 650 


13.2 


58.2 


58.53 


18. 070 


.55.0 


14.9 


59.07 


17. 905 


57.1 


12.9 


59.68 


25. 925 


14.9 


55.1 


58.99 


23.008 


15.0 


56.0 


59.58 


23. 164 


11.8 


56.2 


59.43 


26. 208 


55.2 


14.0 


58.39 


18. 960 


55.4 


14.0 


59.35 


26. 790 


15.0 


56.3 


59.37 


i 29.051 


55.0 


13.1 


58.49 


20 850 


14.7 


50.1 


59.01 


18. 250 


14.0 


56.2 


59. 17 


23.259 ' 


14.5 


57.0 


59.12 


14. 040 


50.5 


13.4 


59.11 


15. 810 


12.1 


56.0 


59.81 


28.333 


12.4 


56.6 


59.23 


11. 188 1 


57.2 


13.0 


59.23 


13.662 


11.9 


56.3 ' 


59.24 1 


27.858 


58.0 


13.6 


58.64 ! 


9.522 


59.0 1 


14.9 


59.62 



88 



UNITED STATES AND MEXICAN BOUNDARY. 



Station Xo. 9, wenieni part of Sulpktir Spring Valley. 



icioiii- 


Le 


■el. 


arting. 


N. 


S. 


t. 




d. 


18. 590 


50.1 


14.6 


18.580 


.52.0 


16.8 


25. 209 


15.4 


51.7 1 


21.985 


19.9 


55.3 


27.729 


14.8 


51.0 


27.210 


17.3 


53.0 


18.401 


16.8 


53.1 ■ 


18.491 


17.4 


52.6 


11.161 


51.7 


14.9 


10.739 


54.0 


18.9 


14. 181 


1G.9 


54.0 


13.606 


17.0 


52 3 


27.431 


52.3 


15.0 


28.449 


10.3 


53.7 


27.851 


17.9 


53.2 


27.874 


53.3 


16.0 


27.820 


54.0 


18.5 


24.281 


18.5 


55.1 


13.701 


18.4 


54.4 


14.090 


1,5.5 


54.0 


19. 579 


18.5 


53.9 


15.889 


17.0 


52.0 


14.262 


52. 


17.0 


14. 754 


51. 9 


18.8 



52.2 
52.8 



K. 


10.530 


53.7 


18.3 


N. 


10.051 


53.2 


16.3 


N. 


18.239 


52.7 ! 


17.2 


N. 


18.167 


53.5 


13.9 


S. 


32.041 


16.9 


52.6 


s. 


31.742 


16.3 ; 


56.2 


s. 


14.529 


17.2 


53.2 



17.0 


50.2 


52.9 


19.2 


18.8 


52.7 


17.7 


51.7 


54.7 


20.8 



17. 940 


17.8 


52.3 


10. 501 


18.8 


53.8 


11.50!) 


15.9 


50.9 


J9. 729 


18.9 


54.0 


29. .'-.10 


17.0 


53. 9 


23.079 


10.9 


.53.1 


25. 071 


52.8 


17.2 


25. 340 


54.0 


16.5 


30. 791 


53.2 


18.0 


19.319 


18.1 


53.8 


19.512 


19.0 


54.9 


14.472 


18.2 


53.9 


14. 641 


18.9 


54.2 


19.760 


17.8 


53.2 


20.285 


16.1 


51.9 


27.928 


52.9 


17.0 



21.737 


16.3 


13.961 


50.9 


13.800 , 


55.3 


12. 875 


50.3 


12. 400 


51.9 


22.319 


52.2 



29.208 ' 
26.771 
26.241 



11.334 


17.9 


53.3 


5.73 


15. 528 


54.7 


18.1 


6.28 


25.813 


52.8 


17.0 


6.40 


26.320 


55.5 


17.0 


5.85 


20.310 


52.9 


17.4 


6.73 


23.752 


50.8 


15.8 


5.64 


25.202 


18.0 


53.2 


6.60 


25. 598 


18.0 


54. 2 


6.17 


11.082 


50.1 


14.9 


6.02 


11. 390 


53.2 


16.7 


6.19 


28.411 


18.9 


54.0 


6.24 


28.450 


15.2 


52.2 


5.97 


21.498 


17.9 


53.2 


6.05 


21.340 


12.0 


52.2 


.5.81 


9.062 


52.7 


16.8 


6.05 


8.810 


57.6 


17.8 


6.62 


24. 591 


53.9 


17.8 


6.26 


28. 721 


52.2 


18.9 


.5.72 


28. 979 


51.0 


17.6 


5.70 


10. 150 


18.1 


. ,52.0 


5.69 


26. 070 


53.7 


19.7 


6.13 



26. 120 


18.1 


52.7 


6.90 


16. 090 


18.8 


53.2 


5.47 


14.270 


14.9 


49.0 


5.86 


26.651 


55.4 


20.7 


6.05 


22. 372 


54.9 


19.9 


6.87 


29.901 


52.2 


17.2 


5.99 


29. 202 


49.0 


13.9 


5.46 


9.670 


.52.0 


10.8 


6.51 


0. 542 


55. 


17.9 


6.34 


17.250 


52. 7 


17.1 


6.53 


14. 040 


18.0 


53.2 


5.67 


14.260 


15.0 


52.8 


5.90 


9.651 


18.0 


53.3 


5.56 


19. 891 


53.2 


17.9 


6.41 


20. 139 


55.0 


19.3 


5.77 


20.260 


54.2 


19.0 


5.87 


26.470 


54.5 


19.0 


5.14 


19.021 


53.4 


17.0 


0.20 


19. 582 


51.9 


16.1 


5.08 


12.3.50 


17.0 


53.0 


5.94 


18. 272 


17.8 


53.8 


.1.50 



UNITED STATES AND MEXICAN BOUNDARY. 



Station No. 9, western part of ^Sulphur Spring Valley — Continued. 



Microm- 
reading. 



1892. 
Sept. 10. 



16.8*7 


53.2 


17.1 


17.081 


57.6 


18.4 


18.625 


49.0 


17.8 


18.280 


54.0 


16.9 


17.610 


51.4 


18.0 


19.738 


16.3 


49.6 


10.269 


19.9 


53.0 


20.070 


52.7 


19.1 


11. 581 


19.6 


53.0 


18.385 


51.0 


17.2 


18.405 


52.6 


18.0 


21.832 


52.1 


18.0 


23.600 


53.6 


18.2 


12.820 


17.7 


33.6 


24.570 


54.0 


17.1 


11. 590 


53.2 


1.1.9 


11.492 


53.9 


18,2 


28.950 


15.2 


53.2 


27. 600 


54.2 


16.0 


28.374 


17.0 


55.6 


28.741 


18.0 


53.3 


13.011 


55.3 


16.9 


12.870 


53.4 


17.8 


21.520 


55.5 


15.9 


22.629 


15.0 


54.9 


30.310 


54.9 


15.0 


12.749 


51.3 


17.0 


27.620 


54.9 


10.9 


16.040 


52.1 


13.0 


15. 305 


50.3 


18.9 


13.110 


51.6 


19.7 


21. 701 


18.0 


50.9 


30.075 


18.9 


52.0 


21.075 


17.5 


51.2 


21.315 


17.0 


51.2 


31.719 


18.1 


52.8 


12.419 


16.9 


53.9 


15,851 


15.0 


52.3 


18, 385 


17.0 


54.2 



20. 580 
29.905 
19. 187 
28.779 
20. 130 
20. 140 
17.515 
16.390 



27.108 
23. 870 
22. 191 



.20 I 

:: i 



One turn of micrometer^62.16'l". 
One division of level^l.28". 
Total, 101 observations on 72 pairs. 
Latitude of Station No. 9 = 31o 20' 06.07" 4- 
There waa no monament near the station. 
"Weight for pairs on which two observations i 



S. Doc. 247- 



-10 



90 



UNITED STATES AND MEXICAN BOUNDARY. 



■ San Pedro Hirer, 1 mile southeast of Monument No. 98. 



Microm- 
eter 
reading. 


Le 


'el. 


N. 


S. 


(. 


d. 


d. 


17. 310 


15.0 


52.7 


10.495 


15.9 


54.7 


13.530 


17.0 


56.0 


12.809 


18.0 


52.7 


22. 962 


13.0 


52.3 


21.826 


19.0 


53.0 


25.808 


55.6 


10.1 


25.302 


51.7 


16.9 


31.369 


53.4 


14.0 


18. 860 


14.7 


54.5 


14.051 


14.1 


54.1 


19. 670 


15.0 


54.8 


18.970 


19.3 


54.1 


27.885 


13.2 


53.3 


28.052 


14.6 


53.4 


28.653 


55.0 


14.9 


22.951 


45.8 


16.2 


22.696 


52.9 


17.9 


17.480 


50.5 


20.2 


21.990 


51.4 


20.7 


30.182 


51.0 


20.0 


15. 200 


18.9 


50.1 


21.770 


18.5 


50.1 


31.371 


50.6 


18.9 


27.051 


53.5 


18.0 


13.305 


18.5 


54.2 


24. 260 


54.1 


18.3 


24.560 


17.8 


53.4 


24. 099 


18.0 


51.9 


26.481 


19.9 


55.4 


26.093 


16.5 


49.3 


17. 218 


16.7 


52.2 


17. 800 


16.1 


54.6 


11.360 


54.1 


18.1 


11. HI 


52.2 


18.1 


28.836 


15.6 


51.5 


29.580 


15.6 


53.4 


28.130 


53.3 


17.1 


27.675 


17.9 


54,0 


27.018 


16.0 


53.8 


28.161 


53.4 


17.0 


23.680 


16.1 


52.8 


22.731 


17.0 


51.9 


13.730 


18.1 


55.0 


13.861 


15.8 


54.3 


19.324 


17.0 


53.6 


18. 080 


17.9 


52.7 


15.650 


16.3 


53.0 


15. 250 


55.6 


18.9 


14.820 


55.2 


15.6 


27. 588 


17.0 


54.0 


20.579 


19.9 


50.4 


11.771 


54.2 


17.0 


10.801 


48.9 


17.9 


18. 840 


54.2 


17.1 


31. 090 


14.0 


51.2 


30. 673 


16.0 


47.7 


14. 399 


16.0 


53.4 


25.182 


53.2 


19.6 


21.960 


54.2 


17.1 


14.100 


53.0 


15.2 


13. 622 


50.9 


19.8 


31.938 


17.0 


55.0 



Microm- 
eter 
reading. 



22. 828 
29. 289 
27. 270 
26.730 

18. 245 
17. 228 
13. 628 
13. 098 

9.060 
20. 575 
26. 932 
20. 049 

19. 390 
10. 825 
10. 990 
11.900 
17. 788 
17. 492 
21.640 



8.320 
12.750 

27. 500 
15. 931 
14. 480 
14. 040 
12. 799 
12.431 
22.310 
22. 900 

28. 701 
28.433 i 

9.070 j 
10.720 
11.118 
12.349 
11.628 I 
10.518 j 
16.141 
15.251 
27.090 
27. 209 
21. 270 
20. 955 
24.710 
25. 004 
24.550 

i2.no 

11. 188 
28.519 
27.450 
20. 900 
9.238 
8.901 



25.670 
9.161 



54.5 
55.4 
55.0 



51.3 
50.9 



56.0 
17.0 
54.9 
52.8 
57.2 
50.9 
53.8 
56.4 



51.9 
15.0 
55.4 
54.1 
54.9 
54.2 
53.0 
51.2 
51.9 



53.2 
50.9 
18.1 
16.2 
17.9 
50.4 
48.8 
53.3 
17.0 
16.8 
16.0 
19.8 
.56.1 



15.6 
16.1 
20.1 
13.0 
21.4 



53.7 
14.6 
14.0 
14.8 



13.6 
55.6 
45.9 
53.9 



20.2 
52.8 



14.0 
51.4 
19.0 
19.0 
18.1 
15.4 
16.5 



55.2 
47.2 
55.0 
13.2 
17.0 
16.0 
51.3 
54.0 



35.51 
35.14 
34.85 
35.01 
35.13 
34.21 
34.74 
34.97 
34.60 
34.91 



34.40 
34.22 
34.30 
34.95 



35.49 
34.70 
35.24 
35.16 
35.35 
35.29 
34.87 



34.29 
34.49 
34. 73 
34.85 
33.98 
34.12 
33.08 
34.18 
35.70 
31.04 
33.61 
35.13 
35.22 
34.38 
34.92 
35.31 
34.93 
34.54 
34.79 
34.44 
34.21 
34.05 
33.52 
34.63 

34.41 
34.32 
34.45 
35.37 
35-48 
34.94 
34.27 
34.94 
34.44 



■ 615 observed 16" late ; Oct . 12, star 598 observed 12- late, 



UNITED STATES AND MEXICAN BOUNDAKY. 



91 



Slation Xo. 10, mar San I'edro Rive 



ill- simlheast of Monument No. 



1892. 
Oct. 13. 



14. 



Microra- 
reading. 



12.618 
25.719 
25.209 
12. 175 
12.374 
28.298 
27.901 
27. 501 
13.281 
12.575 
10.568 

18.797 
31. 980 
19.888 
19. 250 
9.740 
22. 859 
22. 070 
21. 140 



15. 129 

18. 015 
29. 810 
16. 530 
21.619 

9.261 
16.780 

19. 930 
11. 930 
22.491 
15. 461 
21.092 
29. 400 
18. 120 



Microm- 
reading. 



15.415 


14.0 


16.948 


13.0 


16.270 


18.1 


27.258 


56.7 


14. 582 


13.7 


14. 050 


16.0 


26. 991 


17.1 


27. 178 


17.8 


10.961 


52.8 


10. 021 


52.0 


11.700 


18.5 


25.400 


15.0 


24.692 


18.0 


28. 851 


51.9 


19.320 


19.3 


19.416 


18.6 


6.923 


16.9 


21.731 


17.8 


21.281 


15.0 


30. 378 


54.2 


15.581 


53.8 


18.060 


17.5 


17.111 


18.3 


22.125 


17.7 


21.711 


16.2 


27. 418 


51.2 


22.230 


50.8 


13.480 


52.6 


24.200 


53.5 


21.938 


17.1 


8.921 


52.0 


22. 091 


18.9 


17.018 


18.0 


29.877 


18.9 


21.271 


50.9 


19.672 


16.0 


27. 839 


17.4 


16.510 


18.0 



34.38 
34.95 
35.31 



35.30 
XI. 71 
34.41 
34.55 
34.67 
35.59 
34.62 
.34. 91 
35.48 
35.21 
34.66 
35.20 
34.68 
34.95 
35.31 
35.31 
34.53 
35.52 



34.72 
34.01 
34.63 
35.63 



34.55 
34.38 
35.17 
34.95 



One turn of micrometer^62.01 
One (livlsiou of level= 1.28". 
Total, 106 observations on 76 ps 
Latitude of Station No. 10 = 31 
Latitude of Monument No. 98 = 
■ Station No. 10 was on 



19' 34.84" ±0.1 
31° 20' 04.67". 
tbe east side t 



■ tlie San Pedro River ; Monument No. 20 — Emory — was t 



about 1 mile northwest from the station. Near the station is a pile of stones, with Inscription plates, 
boundary monument when locating the station. 

"Weight for pairs on which 2 observations were made, 1.0; one observation, 0.8. 

The mean place for 1892, as used in the latitude computation, was for star No. 63, 18° 40' 50.9" : for 
No. 37, 58" 23' 15.8" ; for star No. 74, 57° 25' 37.4", and for star No. 86, 63'^ 8' 16.5". 



92 



UNITED STATES AND MEXICAN BOUNDARY. 
Station No. 11, 1 mile east of La Noria, Aria., near Monument No. 111. 



Datb. 


Star No. 


N.or 
S. 


Microm- 
eter 


Level. 


fitar No. 


N.or 
S. 


Microm- 
eter 


Level. 


Latitude, 
















reading. 


N. 


S. 




reading. 




H. 


1892. 






(. 


d. 


d. 






t. 


d. 


d. 




Nov. 2 


576 


R. 


20.545 


21.6 


53.8 


578 


N. 


20,303 


52,3 


19.8 


56. 73 




576 


S. 


19. 800 


20.0 


52,2 


678 


N. 


19, 602 


54.0 


21,0 


57.75 




580 


s. 


29. 542 


21.0 


53,8 


682 


N. 


11.864 


52.8 


19.9 


07. 28 


5 


580 


s. 


28. 521 


18.6 


55.3 


682 


N. 


10.883 


67.1 


20.0 


.57. 95 




584 


N. 


29. 048 


54.9 


22.0 


586 


S, 


12, 920 


22.0 


54.8 


57.74 


n 


591 


N. 


23. 320 


62.0 


19.0 


594 


S. 


18, 760 


18.8 


51.9 


57,19 




591 


N. 


22. 991 


51.7 


16.9 


594 


R. 


18, 330 


13.4 


48.8 


66.92 


2 


595 


N, 


18.823 


54.9 


21.5 


596 


S. 


23.618 


21.8 


55.0 


57.70 




595 


N. 


17. 459 


50.9 


15.4 


596 


S. 


22. 213 


16.5 


61,0 


57.10 


2 


599 


N. 


22. 457 


51,2 


17.3 


602 


s. 


18. 050 


16.8 


50.7 


57.07 






N. 


21.618 


50.9 


15,0 


602 


s. 


17. 191 


14,0 


49.9 


57.43 




603 


N. 


31.031 


51.9 


18.0 


608 


s. 


11.230 


17.7 


61.9 


57.52 


2 


609 


S. 


16.568 


20.9 


55.0 


611 


N. 


25. 102 


56.8 


22.3 


58,08 




609 


s. 


15.356 


17.0 


53.5 


611 


N. 


23.930 


54.3 


17.8 


57.02 


2 


613 


s. 


22. 959 


19,0 


53.3 


615 


N. 


18. 920 


54.0 


19.8 


57.17 




613 


s. 


22.379 


17.9 


54.7 


615 


N. 


18, 360 


56.1 


19.2 


57.65 




618 


N. 


32. 312 


54.8 


20.2 


620 


S. 


9.880 


19.0 


63,2 


58.22 


, 




S. 


12. 880 


17.9 


52,0 


5 


N. 


29, 709 


52.8 


18,3 


57.16 


, 


9 


N. 


20. 950 


.54.0 


19.9 


14 


S. 


19.940 


17.9 


52,4 


50. 60 


2 


17 


S. 


19.520 


19.0 


54.1 


23 


N. 


22, 154 


65.0 


20.0 


57. 60 


2 


27 


N. 


19. 240 


52.8 


18,0 


28 


S. 


23,420 


16.7 


51.0 


67,31 


2 


36 


S. 


12.929 


19.9 


54.7 


39 


N. 


29. 070 


56.8 


21.0 


57,03 




46 


N. 


11. 049 


56.1 


20.3 


51 


S, 


32.241 


18.4 


63.2 


57,81 


, 


53 


S. 


17.940 


19.0 


53.9 


60 


N, 


21.823 


.56.2 


21.5 


57.97 




64 


N. 


21.204 


53.4 


18,6 


67 


S. 


21. 529 


17.0 


62.0 


56.72 


2 


73 


S. 


24.160 


21.1 


56,2 


78 


N. 


15.219 


58.3 


22.8 


58.37 




85 


N. 


22.689 


54.9 


19,0 


91 


fi. 


19. 280 


17.0 


53.0 


58.06 


5 


85 


N. 


21.481 


55. 5 


14.2 


91 


R. 


18.099 


14.8 


56.1 


57,63 




94 


N. 


18. 529 


53.3 


17.9 


105 


S, 


23. 890 


15.9 


51.3 


57, 52 


2 


112 


N. 


17.320 


5.3.8 


18,5 


120 


s. 


24. 210 


18.1 


53.0 


57.30 




123 


N. 


28. 530 


63.5 


18,9 


1.13 


s. 


13.381 


17.8 


52.0 


57,68 




137 


S. 


21.611 


17.0 


51.2 


139 


N. 


19. 120 


53.0 


18.6 


57.04 




137 


s. 


20. 887 


17.0 


59.0 


139 


N. 


18. 360 


58.6 


16.7 


57.78 


2 


142 


N. 


22.882 


52,7 


18.1 


147 


S. 


18.382 


15.7 


50.1 


57,93 




153 


R. 


12. 450 


19,8 


54.2 


166 


N. 


29. 240 


53.0 


18.5 


57.43 




153 


S. 


12.229 


18.0 


65.2 


160 


N, 


29,039 


55.1 


18.1 


57,70 




165 


S. 


12. 581 


18.4 


53.2 


167 


N. 


28. 102 


62,0 


17.1 


57,28 


3 


165 


s. 


13. 280 


18.0. 


55.3 


167 


N. 


28.821 


55.7 


18.1 


57, 60 




504 


s. 


32.603 


22.0 


53.7 


507 


N. 


9,112 


53.9 


22.1 


57,41 




504 


R. 


31. 282 


19.9 


55,1 


507 


N. 


7,738 


63,1 


17.6 


67,42 


3 


509 


N. 


24.347 


58,5 


26.8 


512 


R, 


16,538 


25.3 


57.3 


57.52 




514 


N. 


27. 942 


54.1 


22.0 


517 


R. 


14.340 


20,9 


62.9 


56,95 




519 


R. 


14.792 


21.3 


53.3 


521 


N. 


28.281 


54.8 


22.7 


67,10 




523 


S. 


18. 462 


19.0 


51.0 


628 


N. 


23.311 


52.3 


19.9 


57.67 




531 


S. 


28.240 


19.0 


51,8 


535 


N. 


13.889 


53.2 


20.9 


57.14 




531 


H. 


27. 361 


15.1 


54,3 


535 


N. 


13, 040 


57.2 


17.9 


57.02 


3 


537 


S. 


19.010 


18.2 


51,0 


538 


N. 


23, 430 


52,1 


19.2 


66.69 




537 


S. 


17.683 


18.9 


63,2 


538 


N. 


22,089 


53.7 


19,0 


56,69 


3 


539 


S. 


12.070 


17.1 


50,0 


543 


N. 


30, 240 


61.0 


18,0 


56,29 




546 


s. 


31. 120 


21.1 


54,1 


547 


N. 


11, 599 


55.0 


22.0 


56.64 


g 


546 


R. 


29. 431 


18.3 


50,0 


547 


N. 


9.891 


49.2 


17,8 


66.45 


3 


550 


S. 


24. 080 


18.1 


51,6 


553 


N. 


18. 762 


52.9 


19.3 


57.45 




556 


N. 


26. 320 


52.8 


19.3 


557 


R. 


14.759 


17.9 


51.0 


67.49 


3 


560 


N. 


32.001 


64.1 


20.9 


564 


.S. 


10. 320 


18.6 


52.1 


57.25 




566 




20, 268 


21.0 


54.7 


568 


N. 


21.338 


54.0 


20.2 


57.31 


3 


671 


R. 


15. 389 


18.5 


52.1 


674 


N. 


27.673 


51.4 


17.8 


57.48 


3 


577 


S. 


15. 060 


, 17.1 


51.2 


579 


N. 


27.760 


50.1 


16.1 


57.35 


5 


577 


S. 


13.469 


18.0 


64.2 


5T9 


N. 


26. 200 


55.1 


18.3 


57.60 


3 


581 


S. 


20. 330 


18.0 


B2,l 


583 


N. 


21.678 


51.8 


17.7 


57.05 




681 


S. 


19. 100 


17.8 


51,0 


583 


X. 


20.483 


53.1 


19,8 


57.90 


3 


585 


s. 


17. 044 


18.0 


52,1 


588 


N. 


25.500 


61.5 


17.1 


67.06 


3 


592 


X. 


15. 829 


63.1 


18.9 


593 


S. 


26.172 


19.2 


53.4 


57.14 


5 


692 


N. 


15.269 


64.3 


17,0 


593 


s. 


25, 590 


17.8 


54.9 


56.37 


3 


597 


s. 


28. 270 


16.2 


50,9 


598 


N. 


12, 210 


50,6 


16.0 


57.23 


5 


597 


R. 


28. 309 


21.9 


59.0 


598 


N. 


12. 268 


60.0 


22,9 


57.65 


3 


600 


N 


12.235 


52.2 


18,0 


601 


R. 


29, 561 


19.0 


53,2 


57.36 


5 


600 


N. 


11.290 


53.6 


16,6 


601 


R. 


28, 591 


16.9 


63,8 


57.23 


3 


604 


N. 


19. 261 


52.0 


17.7 


606 


S. 


21. 910 


18.0 


52.2 


57.49 


8 


604 


N. 


18.710 


52.5 


16,5 


606 


S, 


21.316 


16.0 


52.1 


57.17 


3 


610 


S. 


32. 161 


17.7 


52.1 


012 


N. 


9.739 


50,9 


16.1 


56.96 



JJov. 8, star 594 observed 16" late: Nov, 2, 



UNITED STATES AND MEXICAN BOUNDAEY. 
Station No. 11, 1 mile east of La Nuria, Ariz., near Monument No. Ill — Continued. 



93 



Microm- 
eter 
reading. 


Level. 


N. 


s. 


(. 


d. 


i 


31.740 


17.6 


55.1 


15. 720 


19.2 


54.0 


16. 781 


17.0 


52.0 


13.341 


53.8 


18.9 


28. 180 


53.6 


18.8 


23. 145 


53.1 


18.2 


27.74C 


55.8 


20.7 


16.442 


17.9 


52.8 


27.052 


54.8 


19.9 


12. 970 


51.7 


16.8 


23.530 


52.7 


17.3 


20. 014 


54.1 


18.8 


28. 148 


53.8 


18.0 


22.430 


18.2 


54.5 


21.490 


18.0 


56.6 


24.220 


18.0 


55.0 


23.639 


16.7 


56.0 


19. 110 


55.2 


17.0 


17.565 


56.0 


18.0 


16.549 


55.5 


16.0 


l2. 1.58 


21.0 


52.7 


21.570 


50.4 


17.9 


21.561 


53.7 


16.6 


19. 091 


52.3 


19.3 


18.491 


53.0 


16.9 


24. 369 


16.1 


50.1 


24.714 


15.5 


54.3 


10. 590 


17.1 


51.2 


11. 075 


52.2 


17.7 


11.070 


47.8 


16.2 


13.679 


17.3 


52.8 


12. 199 


50.4 


15.0 


12.242 


49.0 


17.0 


27. 710 


17.8 


53.1 


27.810 


19.8 


51.7 


28. 391 


19.0 


55.0 


27.888 


54.3 


18.0 


13.389 


53.1 


15.9 


13.210 


52.9 


18.3 


12 330 


18.1 


55.1 


17. 642 


19.7 


57.2 


27.058 


17.1 


55.1 


26.982 


15.0 


52.2 


29. 160 


14.9 


53.0 


28.602 


17.0 


54.6 


26. 889 


17.8 


57.7 


32. 159 


56.1 


15.8 


25.719 


14.6 


55.1 


15. 709 


54.9 


13.6 


16. 673 


15.6 


57.0 


18. 322 


15.0 


66.7 


20. 611 


13.9 


55.9 


23.249 


19.7 


51.9 


30. 865 


16.0 


53.6 


16.713 


53.4 


16.0 


17.831 


56.7 


17.0 



Microm- 
eter 
reading. 



9.351 
26.398 
25. 201 
27. 849 

14. 910 
19. 185 
13. 893 
25. 090 

15. 814 
29.491 
18.192 

21. 950 
14. 140 
19. 332 
18.451 
17.342 

16. 781 
22.745 
23. 56] 

22. 560 

29. 738 
16. 910 
16.841 
21. 889 
21.231 
13. 579 
13. 991 

30. 470 



26. 804 

27. 601 
27.651 
11.728 
11. 822 
10. 520 
12.653 
26. 120 



13. 815 
9.952 
9.450 
12. 360 
7.620 
13. 752 
24. 901 
22.928 
21. 

18. 640 
15. 070 
9.452 

22. 860 

23. 052 



Nov. 8, star 522 observed 19- late. 

One turn of micrometir = 62.124". 

One division of level = 1.28". 

Total, 126 observations on 92 pairs. 

Latitude of Station No. 11 =31° 19' 57.38" i 0.03". 

Latitude of Moniunent No. Ill = 31° 19' 57.58". 

Latitude Station No. 11 was 2.0 meters east and 6.2 meters south of Monument No. 111. 

Weight for pairs on which 2 observations were made, 1.0; one observation, 0.6. 

The mean place for 1892, aa used in the latitude computation, was for star No. 28, 14° 53' 10.3" 
123, 35^ 40' 04.2" ; for star No. 147, 24° 50' 04.1" ; for star No. 167, 62° 51' 58.2" ; for star No. 37, 58° i 
star No. 65, 460 26' 59.8", for star No. 74, 57° 25' 37.4"; for star No. 86, 03° 08' 16.5"; for star No. 
25' 24.8". 



16.8 
54.2 
54.2 
54.0 
56.2 I 
17.9 
54.9 I 
51.8 j 
53.2 
54.3 
53.9 
17.9 
20.7 
18.6 
15.9 
54.8 
56.0 
56.2 
23.0 [ 
52.2 I 
53.9 
54.0 
53.2 



57.3 
12.9 
55.1 



56.99 
57.32 
57.98 



57.32 
57.74 
57.18 
67.80 
57.04 
56.99 
57.74 
58.13 
57.16 



57.72 
57.41 
57.40 
57.27 
66.93 
57.35 
57.18 
57.42 
57.24 



56.95 
56.90 
66.82 
66.84 
57.19 
57. 21 
57.36 
57.48 
57.37 
57.11 
56.72 
57.03 
57.67 
57.27 
57.46 
57.31 
57.92 



.. 91, 11° 46' 14.2" 
star No. 52, — 1° 
1.3", and for stai 



94 



UNITED STATES AND MEXICAN 150UNUARY. 



Station No. 12, Nogales, Ariz., near Monument Ko. 122. 



Date. 


Star No. 


N.or 


Microm- 
eter 


Level. 


Star No. 


N.or 
S. 


Microm- 
eter 


Level. 


















reading. 








reading. 








1892. 






t. 


d. 


d. 






t. 


d. 


d. 




Nov. 19 


580 


S. 


29. 258 


20.8 


54.0 


582 


N. 


11.349 


52.6 


19.0 


4.83 


23 


580 


S. 


28. 724 


17.7 


52.0 


582 


N. 


10.881 


54.1 


19.0 


5.01 


19 


584 


N, 


28.426 


05.1 


21.1 


580 


S. 


12.491 


21.7 


5S.9 


4.01 




58i 


N. 


28, 343 


50.0 


21.7 


580 


S. 


12. 420 


22.9 


51.1 


4.11 


19 


591 


N. 


22.998 


52.8 


18.0 


594 


s. 


18.649 


18.7 


53.3 


4.48 


26 


591 


N. 


22. 330 


48.0 


19.2 


594 


s. 


17. 995 


20.7 


49.2 


4.54 


19 


603 


N. 


30. 430 


54.9 


18.9 


608 


s. 


10. 808 


17.9 


54.1 


4.77 


26 


603 


N. 


29.627 


50.0 


20.8 


608 


s. 


9.979 


21.0 


50.9 


3.35 




609 


S. 


15. 879 


19.0 


55.2 


611 


N. 


24.201 


.55.3 


19.0 


5.04 


26 


609 


s. 


15.811 


21.5 


51.1 


611 


N. 


24.142 


50.2 


20.0 


4.36 




613 


s. 


22. 870 


17.0 


53.7 


615 


N. 


18. 648 


54.0 


17.1 


3,88 


26 


613 


s. 


22. 610 


20.0 


50.1 


615 


N. 


18.340 


49.8 


19.3 


6.33 




618 


N. 


30.701 


54.2 


17.8 


620 


S. 


8.451 


17.0 


54.0 


4.75 




618 


N. 


31.008 


50.3 


19.9 


620 


s. 


8.709 


20.2 


51.0 


4.90 


19 




S. 


12. 000 


17.0 


.541 


5 


N. 


28.649 


54.2 


16.9 


3.97 




9 


N. 


20.491 


54.0 


16.2 


14 


s. 


19. 680 


15.9 


54.0 


3.27 


20 


9 


N. 


20.080 


51.2 


19.9 


14 


s. 


19.300 


20.3 


52.2 


4.22 




17 


S. 


18.836 


17.0 


55.1 


23 


N. 


21.262 


55.0 


16.3 


4.94 


19 


27 


N. 


IS. 679 


54.1 


15.6 


28 


S. 


23.061 


16.0 


54.9 


3.98 


19 


36 


S. 


12.652 


15.0 


54.0 


39 


N. 


28.591 


54.0 


14.7 


4.27 


19 


44 


S. 


27.359 


19.0 


58.9 


49 


N. 


12. 660 


58.3 


18.7 


5.08 


19 


53 


s. 


17.579 


22.0 


52.3 


60 


N. 


21. 228 


51.7 


21.0 


5.05 




53 


s. 


18. 350 


16.0 


49.6 


CO 


N. 


22. 003 


47.9 


14.2 


5.04 


19 


64 


N. 


19.911 


50.9 


20.0 


67 


S. 


20.459 


20.1 


51.1 


4.53 




74 


N. 


11.724 


50.9 


19.9 


80 


s. 


28. 450 


20.0 


51.1 


5.77 






N. 


21.589 


49.4 


18.1 


91 


s. 


18.371 


18.3 


50.0 


4.44 


23 


85 


N. 


21.760 


54.0 


14.0 


91 


s. 


18. 549 


14.1 


54.2 


5.32 






N. 


17.401 


48.8 


17.0 


105 


s. 


22.973 


17.4 


49.2 


4.58 


23 


94 


N. 


17 420 


54.9 


14.9 


105 


s. 


23. Oil 


10.0 


56.1 


5.21 






N. 


16.429 


51.0 


19.0 


120 


s. 


23.520 


19.2 


51.7 


4.90 




123 


N. 


28.299 


51.8 


19.2 


133 


s. 


13.324 


19.3 


52.0 


4.19 




137 


S. 


21.032 


19.7 


52.0 


139 


N. 


18. 330 


51.1 


18.7 


4.48 


22 


137 


s. 


21.45* 


18.0 


53.1 


139 


N. 


18. 768 


54.0 


18.8 


5.52 




142 


N. 


21.929 


53.2 


21.0 


147 


s 


17. 639 


21.0 


54.0 


4.53 


19 


153 


S. 


11.423 


19.0 


52.0 


1,56 


N. 


28.041 


50.9 


17.9 


4.75 




160 


s. 


23. 700 


20.4 


53.4 


102 


N. 


16.613 


52.7 


19.2 


5.31 


22 


100 


s. 


23.787 


18.0 


53.9 


102 


N. 


16.741 


54.1 


18.0 


5.04 


19 


165 


s. 


12.490 


19.2 


52.9 


107 


N. 


27. 821 


52.0 


18.8 


5.12 






N. 


18.189 


65.0 


21.0 


188 


S. 


22. 060 


21.5 


55.7 


6.00 


23 


186 


N. 


18.110 


51.7 


20.9 


188 


s. 


21.955 


21.0 


52.1 


5.07 




548 


S. 


14. 069 


20.3 


48.3 


549 


N. 


26 902 


47.8 


19.2 


4.48 


22 


548 


s. 


13. 551 


19.0 


on.i 


549 


N. 


20. 349 


48.0 


16.4 


4.63 


21 


550 


s. 


23.439 


23.8 


52.1 


553 


N. 


17.851 


.52. 1 


23.7 


4.81 


21 


556 


N. 


25. 230 


49.9 


21.0 


557 


S. 


13. 908 


19.2 


48.2 


4.90 


22 


551 


N. 


27. 122 


51. 6 


19.9 


555 


s. 


10.990 


18.1 


50.6 


3.80 


22 


558 


S. 


27. 778 


20.0 


52. 3 


559 


N. 


11.518 


53.0 


20.0 


5.20 


23 


558 


S. 


28.219 


19.2 


50.2 


559 


N. 


11.929 


49.9 


18.8 


5.69 




500 


N. 


3D. 930 


52.0 


19.0 


504 


S. 


9.477 


16.9 


50.3 


4.27 


22 


566 


R. 


19. 069 


18.0 


51.7 


508 


N. 


19.959 


53.2 


19.4 


4.64 


22 


571 


S. 


14. 322 


17.9 


52.0 


574 


N. 


20.462 


53.9 


19.3 


3.74 


22 


576 


S. 


20.041 


19.2 


54.1 


578 


N. 


19. 621 


55.1 


19.9 


4.53 


26 


576 


s. 


20. 250 


24.0 


52.0 


578 


N. 


19. 793 


51.8 


23.2 


4.73 


22 


581 


s. 


19. 951 


19.3 


55.2 


583 


N. 


21. 120 


56.3 


20.3 


4.15 


26 


581 


s. 


19.479 


21.5 


50.0 


583 


N. 


20.607 


49.6 


21.0 


4.38 




585 


s. 


16. 101 


10.0 


52. 2 


588 


N. 


24.440 


54.0 


17.0 


2.91 


22 


592 


N. 


14. 980 


54.4 


17.6 


593 


S. 


25.482 


15.7 


52.8 


4 39 


23 


592 


N. 


15. 040 


51.3 


15.5 


593 


s. 


25.551 


15.0 


51.1 


3.80 


22 


595 


N. 


17. 647 


54.0 


16.7 


590 


s. 


22.589 


14.8 


52.1 


4.83 


26 


595 


N. 


17. 270 


49.9 


21.0 


590 


s. 


22.279 


21.5 


.50.4 


5.43 


22 


599 


N. 


21. 680 


53.1 


15.0 


002 


s. 


17.439 


13.1 


51.3 


4.40 


26 


599 


N. 


21.769 


49.9 


20.6 


602 


s. 


17. 592 


21.0 


50.9 


4.73 


22 


604 


N. 


18. 508 


54.9 


10.2 


606 


s. 


21.370 


53.2 




4.72 


22 


610 


S. 


31. 098 


15.4 


54.5 


612 


N. 


9.101 


55.9 


16.9 


6.09 


23 


610 


s. 


31.878 


18.0 


55.3 


612 


N. 


9.301 


50,0 


18.8 


4.72 


22 


614 


s. 


14. 968 


16.3 


55.8 


619 


N. 


25.401 


57.9 


18.0 


8.04 


22 


3 


s. 


16. 569 


22.0 


53.2 


8 


N. 


24. 881 


55.5' 


24.2 


4.70 


22 


12 


N. 


12. 519 


52.0 


20.8 


16 


S. 


27.209 


19,0 


50.3 


6.57 


22 


18 


N. 


26.961 


52.1 


20.4 


29 


s. 


13. 801 


18.0 


50.2 


4.33 


22 


37 


N. 


22. 092 


48.9 


10.2 


45 


s. 


18. 300 


15.1 


48.0 


5.10 


26 


37 


N. 


22. 079 


53.9 


21.0 


45 


3. 


18.290 


22.3 


55.3 


4.01 


22 


46 


N. 


9 981 


50,0 


17.0 


51 


s. 


31.308 


16.6 


49.3 


5.20 



UNITED STATES AND MEXICAN BOUNDARY. 
Station No. IS, Nogales, Ariz., near Monument No. /2J— Continued. 



95 



Microm- 
eter 
reading. 



24.511 
23. 708 
22.290 
19.301 
26.780 
22.541 

15. 070 

16. 780 
27. 787 
27. 509 
14.821 
17.650 
16. 595 
17.088 



27. 118 
29. 802 
31. 120 



26.570 
32. Ill 
26. 119 



20.918 
18. 518 
26.288 
11. 033 
23. 382 
13. 880 
21. 602 
13. 392 
15. 570 
17. 931 
21.373 
24. 179 
11. 332 



24. 341 
15. 010 
15. 390 
17. 510 
17. 159 
21. 358 
12. 950 
18.739 



13. 060 
24. 967 
23. 048 

22. 790 
23.304 
27.411 
10. 622 

14. 219 
26. 195 
26. 141 

11. 979 
28. 581 
27.881 
23. 173 
13. 720 
10.419 

9.452 

23. 021 
22. 483 
13. 028 

12. 873 



25.441 
18. 808 
21. 903 
15. 009 
29. 140 
14. 918 
26. 305 
16. 142 
25. 799 
24. 948 
21. 325 
18. 112 
14. 502 



1.340 



14.3 
53.0 
17.0 
56.0 
54.5 
54.8 
57.8 



49.9 
49.9 
51.0 
21.0 
53.6 
52.0 



50.9 
49.8 
53.2 



54.9 
18.9 
16.2 
16.0 
52.9 



4.57 
5.08 



5.14 
4.94 
4.61 
5.37 
5.08 
5.48 
5.32 
3.25 
5.18 
5.43 
5.50 
4.50 
4.97 
4.36 
4.12 



One turn of micrometer=62.124". 

One division of level = 1.28". 

Total, 121 observationa on 93 pairs. 

Latitude of Station No. 12 = 31^ 20' 04.77"+ 0.04". 

Latitude of Monument No. 122=31^ 20' 00.73". 

Latitude Station No. 12 was 124.4 meters north and 170 meters east of Monument No. 122, in the grounds 
Montezuma Hotel. 

Tbe latitude and longitude piers, bnilt of brick and cement, were left in position. Tliese same i 
tbe year by tbe Ooiist and Geodetic Survey. 

Weight for ptiirs on wliich two observations were made, 1.0; one oliservation, 0.7. 

The mean place for 1892, as used in the latitude computation, was, for star No. 28, 14° 53' 10.3"; for star No. 74, 57° 25' 37.4 
No. 91, 11° 46' 14.2" ; for star No. 123, 35 ■ 40' 04.2" ; for star No. 147, 24° 50' 04.1" ; for star No. 167, 62° 51' 58.2" ; for star No. 37, 58 ■ 23' 1 
for star No. 65, 46° 20' 59.8" : for star No. 86, 63° 08' 16.5" ; for star No. 99, 34° 28' 34.3" ; for star No. 135, 9° 39' 28.3" ; for star No. 192, 4 
24 8", and for star No. 52, —1° 33' 06,1". 



built and used e.arlier 



for 6 



96 



UNITED STATES AND MEXICAN liOUNDARY. 

Station jN'i). 13, Yuma, Ari:., in corral of qiiartermaster'a department. 

Microm- 
reading. 



28. 819 
22. 024 
21.747 
22.464 
22.259 
21. 230 
21. 070 

21. 027 

30. Oil 

29. 759 
29. 725 
30.127 
23.511 
24.010 
23.921 
23.871 I 
29. 669 
29.370 
30. 184 
22. 186 

22. 210 
10.741 
10. 708 
32. 274 
32.76 

23. 308 
24. 160 

23. 763 
23.675 

31. 632 
31. 468 
16.480 

24. 216 



24. 241 
18.911 
18. 638 
21.640 
21.412 
15. 860 
15. 930 



14. 909 
16. 143 
16.216 
16. 511 
13. 650 

9.640 
10. 071 

9.849 
13.381 



17.0 
52.3 
18.0 
16.7 
18.9 
15.7 
21.6 
18.9 
50.2 
49.0 
18.7 
19.0 
53.0 
50.2 
51.8 



53.3 
53.0 
52.5 



17.2 
53.9 
53.2 



49.6 
19,9 
50.8 
49.7 



50.7 
51.1 
51.2 
52.0 



17.2 
53.2 
53.1 



Microm- 
eter 
reading. 


Level. 


Latitude, 


N. 


S. 


32=> 43'. 


(. 


d. 


d. 




19. 840 


51.0 


18.6 


34.93 


15.752 


18.9 


51.3 


34.61 


30. 341 


61.2 


18.2 


34.12 


29. 160 


50.9 


18.0 


34.67 


28.761 


49.3 


18.0 


34.19 


28. 527 


47.9 


16.8 


34.20 


12.109 


56.0 


23.9 


34.64 


12.619 


49.9 


18.8 


34.86 


18.780 


15.7 


48.7 


34.47 


18. 569 


18.1 


49.7 


.34.92 


17. 680 


53.3 


20.2 


34.38 


17.410 


49.3 


18.0 


34.53 


19. 223 


17.9 


51.1 


34. 56 


19. 119 


18.6 


50.1 


34. 90 


19. 037 


19.2 


50.3 


34.46 


11. 200 


50.3 


17.9 


33.63 


10. 986 


65.1 


21.6 


35.03 


10.879 


51.0 


19.3 


34.66 


11.318 


51.9 


20,8 


34.86 


17.319 


60.8 


17.9 


34.41 


17. 852 


,53.1 


19.0 


34.72 


17.708 


51.2 


19.7 


34.67 


17. 702 


52.7 


21.1 


34.49 


10.283 


51.7 


18.9 


35.14 


9.996 


50.9 


19.0 


34.69 


10. 841 


49.0 


17.7 


35.06 


18. 371 


51.0 


17.9 


34.98 


18.408 


49.1 


16.9 


34.66 


30.890 


17.6 


52.8 


34.30 


.30.889 


18.8 


50.9 


34.52 


6,651 


18.8 


50.6 


34.59 


7.140 


18.9 


51.8 


34.52 


15.718 


19.3 


53.4 


35.28 


16.601 


19.0 


54.2 


35.15 


16. 192 


19.0 


51.6 


35.07 


16. 493 


16.8 


60.9 


34.82 


7.971 


19.2 


63.2 


34.28 


7.790 


18.2 


50.9 


34.13 


23. 839 


18.6 


54.0 


34.68 


16. 781 


53.5 


18.9 


34.03 


16.809 


51.9 


15,9 


33.73 


16.918 


52.2 


17.0 


34.78 


16.780 


50.9 


17.0 


34.32 


21.599 


21.7 


57.0 


34.78 


21.311 


17,8 


52.9 


34.96 


18, 272 


19.6 


55.3 


34.69 


18. 006 


17.9 


53.0 


34.15 


24. 160 


54.1 


18.6 


34.31 


24. 250 


53.3 


17.9 


34,43 


25. 938 


16.0 


51.4 


34.12 


20.219 


18.9 


54.8 


34.16 


26.483 


16.0 


61.9 


35.18 


26.367 


15.9 


51.2 


34.66 


25, 650 


17.0 


52.6 


34.66 


25,692 


15 3 


51.7 


34.40 


26. 008 


16.0 


51.7 


34. 7B 


28. 683 


54,1 


17.9 


35.39 


30. 350 


53.2 


17.9 


34.51 


30.800 


53.7 


17.7 


34.26 


29. 839 


15.8 


52.0 


34.68 


26.960 


17.0 


62.6 


34.96 


27. 069 


20,0 


66.3 


34.66 



UNITED STATES AND MEXICAN BOUNDARY. 



97 



Station Xo. 13, Tun 



nl of quartermaster's department — Continued. 



1893. 
Jan. 18. 



Z_L 



24.034 


17.0 


53.6 


23.840 


16.0 


52.8 


9.03U 


1.5.4 


51.8 


9.431 


16.3 


5;i.2 


9.159 


18.0 


54.2 


9. 033 


17.9 


54.8 


30. 276 


53.0 


10.3 


30. 468 


52.7 


15.6 


30. 674 


53.2 


17.0 


30.500 


55.0 


17.5 


19. 120 


18.0 


S4.8 


19.252 


16.9 


54.1 


18.759 


17.0 


53.0 


18.799 


16.6 


53.9 


8.900 


56.5 


19.0 


8.470 


53.3 


17.3 


27.481 


15.9 


53.2 


27.952 


16.1 


53.9 


12.681 


15.0 


53.0 


13. 272 


15.7 


51.8 


18. 349 


17.0 


54.3 


17. 978 


15.1 


53.3 


10.401 


18.6 


56.2 


9. 672 


16.1 


52.3 


26.558 


53.4 


16.0 


26. 586 


53.0 


15.6 


25.680 


53.2 


16.9 


20.851 


55.1 


16.6 


13.891 


53.3 


15.9 


14.111 


55.1 


16.0 


22. 561 


16.5 


53.9 


24.019 


57.4 


19.2 


13. 925 


54.6 


16.9 


14. 149 


55.1 


17.7 


21.932 


16.8 


55.0 


22.531 


16.0 


53.9 


22. 501 


18.1 


56.2 


16. 200 


55.5 


17.0 


15. 892 


54.8 


17.0 


15.859 


54.0 


16.0 


26.790 


17.1 


55.9 


26.811 


15.6 


5:'. 3 


26.560 


14.8 


52.8 



One turn of the micrometer^62.124". 

One division of level=1.28". 

Total, 105 observations on 45 pairs. 

Latitude of Station No. 13 = 32o 43' 34.69" ±0.03". 

Station No. 13 is in the east room of the adoln- h 1 1 i 1 . 1 1 ii - w h i . ■ 1 1 fi .r 
Department, U. S. A. It is markfd by a brickand ctnK ni i.i.-i w li nh 
party. The latitude computation for this station iii;i'i.' t\\<- |.TnKiM.- 
meaii of two star declinations J:0.02". As it is certain tlijt tli. dci liii;. 
assigned on the assumption that tlie probable error of tho mean of two 

Weiglit for pairs observed once, I.O; twice, 1.4; three times, 1.6; 

The mean place for 1893, as used in the latitude computation was 
No. 99, 34° 28' 51.5"; for star No. 123, 35° 40' 20.3"; for star Xo. 13.5, 9° 3 
for star No. 192, 47° 25' 34.7" ; for star No. 223, 60° 17' 06.5" ; for star No 
46° 49' 45" 



Microm- 


Level. 


rea!u;.g. 


N. 


s. 


(. 


d. 


d. 


17.259 


53.1 


16.6 


17.078 


53.0 


16.3 


30. 809 


62.2 


16.0 


31.219 


53.3 


16.7 


30.968 


55.1 


19.0 


30. 811 


65.1 


18.0 


9.709 


15.0 


51.7 


9.921 


14.9 


61.9 



21.560 
21.101 
21. 125 
31.530 
31. 081 
12. 683 
13.121 
28.110 
26.719 
22.391 
22.012 
30.929 
30.250 
14.740 j 
14.799 
13.849 j 



26.729 
19. 309 
16.899 
27.411 I 
27.528 
17.958 
18.520 I 
18.480 
24.870 
24.600 
24.574 
13.990 
14.029 



16.4 
54.0 
54.0 



17.0 j 
54.9 j 
52.7 
16.3 

16.4 ! 

16.5 ' 
17.0 

16.3 
21.0 
18.0 
51.3 j 
52.0 ! 
51.2 i 
53.8 j 
54.3 



56.3 
54.0 
17.2 



34.66 
35.02 
34.90 
34.53 
34.71 
35.21 



34.48 
35.65 
34.58 
35.07 

34.57 



34.92 
35.98 
35.43 
34.15 
34.91 
35.28 
35.31 
34.46 
34.43 
35.58 
34.68 
34.52 
35.66 
34.39 
33.87 
34.98 
34.71 
34.50 
35.69 
34.87 
34.71 
34.69 
35.08 



t of the north wall of the old corral of the Quartermaster's 
and used in 1892 by a Coast and Geodetic Survey longitude 

;i single observation :»:0.28", and the probable error of the 

irs are much larger, the weights for the separate pairs were 

ions was 0.9 of the probable error of a single observation. 

IS, 1.7. 
No. 91, 11° 46' 31.8"; for star No. 97, —0° 51' 13.2"; for star 

for star No. 147. 24° 50' 18.3"; for star No. 107, 62° 52' 10.2"; 

20' 11.8"; for star No. 227, 41° 05' 21.4"; and for star No. 230 



UNITED STATES AND MEXICAN liOUNDAKY. 
Station No. 14, 20 miles helow Yuma, Ariz., near Monument No. 204. 



Z_L 



Microm- 



4Canielop 
I Ami J 



E.J. 
22 H. 

J. 
51 Aiiri 



J.Orocn 

1460 



23. 178 
18. 399 
29. 361 



26. 741 
12. 930 



22. 590 
9.851 



24. 958 
8.169 



9.494 


52.9 


15.021 


54.2 


15.820 


16.3 


16.516 


18.6 


24.772 


54.0 


16. 204 


52.0 



10 Mono- 
cenitis 



I eGemin / 



</< Gemin . 
P. 774 
P. 790 



16. 288 
22. 018 
10. 061 



12. 149 
25. 659 
27. 380 
29. 901 
17. 050 



23. 061 
28. 338 



19. 487 
28. 994 



15.732 
22. 423 



19.8 
52.0 



One turn of micrometer = 62.1 24". 

One division of level = 1.28". 

Total, 25 observations on 24 pairs. 

Latitude of Station No. 14 = 32° 29' 01.12" f 0.08". 

Latitude of Monument No. 204 = 32° 29' 0.91 ". 

Latitude Station No. 14 was 6.4 meters north and 1.5 meten 

Tlie only pair which was observed twice was given weiglil 

Tlie mean place for 1893, as used in the latitude ( 

February li, star Ko. 249 observed 25- late. 



west of Monument No. 204. 
1.4, and the other pairs weight 1. 
, was, for star No. 217, 8° 42' 57.9 



• No. 229 24° 07 23.95" 



UNITED STATES AND MEXICAN BOUNDARY. 



99 



station No. 15, 13 miles south of San Diego, Cat., near Monument No. 2SS. 



1893. 
Sept. 27. 

Oct. 1. 

2. 

Supt. "i?. 

30. 

30. 

30. 
Oct. 2. 
Sept. 30. 

Oct. 1. 

Sept. 30. 

30. 

Oct. 1. 

2. 

Sept. 30. 

30. 
Oct. 2. 
Sept. 30. 
Oct. 2. 
Sept. 30. 

Oct. 2. 

Sept. 30. 
Oct. 2. 
Sept. 30. 
Oct. 2. 
Sept. 30. 

30' 
Oct. r 
2' 
Sept. 30. 
Oct. 1 . 
2, 
Sept. 30. 
Oct. 2. 
Sept. 30, 

30 
Oct. 1 
Sept. 30 
Oct 1 
Sept. 30 

30 
Oct. 2 
Sept. 30 



B.J. 
/3 Cygni 



W AquariiJ 

( '■ ] 
(31 Cepliei) 



Microm- 
reading. 



26. 271 
20. 738 
20. 268 
26. 149 
31. 069 

14. 979 

12. 690 
15. 480 
16. 170 



10. 130 
12.734 



28. 121 
25. 552 
18. 885 

18. 621 
19.410 
21.970 
22. 741 
22.431 
12. 138 
12. 121 

19. 850 
19. 390 
18.748 
10. 660 
16.858 
26.218 
16. 623 
15. 988 



10. 409 

9.090 
29.989 
21. 889 
12. 361 
29. 221 
20. 509 



14.! 



51.2 

14.0 ;{ 



I 15 Cygni I 

( '■ \ 

\ 15 Cygni ) 

( .1. ) 

I 15 Cygni J 

/ J- 1 

^ 15 Cygni J 

493 



E.J. 
61 Cygni Pr 



* Observed wrong star ; rejected. 



Microm- 
reading. 



28. 350 
22.450 
23. 180 



29. 566 

27. 691 

28. 720 



18. 349 
10. 963 
10. 842 
14. 590 
20. 470 
20. 210 
20.980 
16.819 
17.629 
17. a82 
28. 300 
28. 279 
20. 650 
21.438 
20.181 
23. 120 
23. 300 

14. 979 
23. 779 
23. 162 
20. 900 
28. 519 

27. 825 
9.299 

15. 988 
27. 317 

9.477 
19. 409 
26. 963 
13. 390 
18.746 



17.8 


51.2 


56.6 


13.3 


13.0 


55.8 


15.5 


52.2 


19.9 


53.2 


14.2 


57.1 


18.0 


.■)4.7 


18.3 


52.0 


55.6 


12.9 


51.0 


17.8 



100 



UNITED STATES AND MEXICAN BOUNDARY. 



Station iVb. 15, IS miles south of San Diego, Cat., near Monument No. 25S — Continued. 



Star No. 


N.or 
S. 


224 


N. 


227 


N. 


P. 509 


S. 


239 


s. 


246 


N. 


P. 600 


N. 


f '■ 1 




Draco. 


N. 


1 uia j 




P. 1646 


N. 


P. 171.5 


N. 


502 


S. 


J. 1 




73 Draco- \ 


N. 


His J 




( ^■'- \ 


N. 


trCygni / 




l74Cygni/ 


N. 




562 


N. 


580 


S. 


501 


N. 


, J. ( 




IxAndroni/ 




; E-J- I 


S. 


UPi3cium' 




4 


s. 


15 


s. 


28 


s. 


60 


N. 


121 


S. 


121 


s. 


128 


s. 


134 


s. 


149 


N. 


173 


s. 


191 


s. 


199 


N. 


P. 444 


S. 


228 


S. 


232 


N. 


241 


S. 


250 


N. 


{ 3L3Tffl } 


N. 


{ .Lyrle J 


N. 


494 


S. 


533 


s. 


{e&} 


s. 


564 


s. 


( 13 LacertiE/ 


N. 


24 


N. 


107 


S. 



20. 972 
24.049 
17. 301 
14. 774 
18.599 
8.175 



17.379 
27. 861 
10. 671 



10. 191 


52.2 


20. 175 


53.4 


11.970 


52.8 


21.879 


17.0 


22. 018 


52.2 



25. 901 

27. 691 
11.172 
13. 817 

26. 061 
18. 820 
18.561 
11. 842 
18.209 

21. 139 
30. 909 

27. 762 



10. 151 
24. 748 



30.711 
8.941 

27.719 

23. 180 
9.169 

11.432 



53.1 



Star No. 


N.or 
S. 


226 


S. 


229 


S. 


235 


N. 


242 


N. 


249 


S. 


253 


S. 


473 


s. 


477 


s. 


498 


s. 


509 


N. 


(,.:.„) 


s. 


p. 1928 


s. 


/ J- I 
I xPegasi / 

p. 2104 


s. 


N. 
S. 


614 


s. 


I » Cassiop / 
5 


N. 

N. 


23 


N. 


31 


N. 


68 


S. 


123 


N. 


123 


N. 


132 


N. 


{ .pLi } 


N. 


155 


S. 


P. 350 


N. 


193 


N. 


\ cTauri / 


S. 


P. 477 


N. 


230 


N. 


244 


S. 

N. 


P. 605 


S. 


P. 1621 


s. 


P. 1609 


s. 


P. 1771 


N. 


543 


N. 


560 


N. 


572 


N. 


586 


s. 


33 


s. 


71 


N. 


111 


N. 



Microm- 
reading. 


Level. j 


N. 


S. 


18.720 
15.321 
24.051 
26.231 
18. 990 
30. 165 


d. 

13.8 

13.0 

59.4 

59.2 

13.0 

11.8 


d. 

51.7 

58.2 

13.6 

13.2 

68.0 

56.1 


14.609 


16.9 


48.0 


19. 780 
8.459 
28.700 


20.3 
21.0 
52.8 


51.9 
54.1 
19.0 


29.560 


17.9 


51.8 


29.091 


18.3 


52.2 


18.470 


18.1 


52.9 


27.560 


18.9 


52.1 


16.749 


50.0 


16.9 


18. 509 


19.0 


52.1 


26. 748 


17.0 


50.9 


12. 800 


51.3 


16.9 


11.481 
29. 472 
26.571 
13. 648 
22.581 
22. 321 
28.223 


53.0 
50.8 
51.7 
18.3 
52.2 
53.2 
50.3 


18.0 
15.1 
15.9 
54.2 
15.5 
20.3 
13.9 


19.600 


53.4 


16.0 


18.788 
10.681 
10. 169 


16.8 
53.2 
54.0 


55.0 
12.9 
13.8 


16. 021 


17.0 


57.0 


24.949 
27. 318 


53.1 
53.0 


14.8 
15.2 


30.510 


17.2 


53.8 


26.862 
28. 390 


53.0 
17.8 


15.0 
57.0 


14.688 


17.7 


47.3 


10. 740 


18.2 


48.8 


12.731 
16. 186 


52.8 
50.6 


22.0 
19.1 


8.749 


50.1 


19.1 


29. 808 


50.1 


19.3 


13. 909 


20.3 


51.2 


16.626 
30. 470 
29. 259 


19.0 
52.8 


53.0 
17.9 
20.0 



Total, 96 observatic 






Onu turn of micrometer = 62.059". One division of level = 1.28". 

Latitude of Station No. 15 = 32° 32' 01.36" + 0.04". 

Latitude of Monument No. 258 = 32° 32' 01.34". 

Latitude Station No. 15 was 0.6 meters north and 5.1 meters east of Monument No. 258. 

Weight for pairs on which one observation was made, 1.0: two observations, 1.2: three observations. 1.3; four observations, 1.3. 

The mean place for 1892, as used in the latitude computation, was for star No. 65. 46° 27' 18.5" ; tor star No. 74, 57° 25' 55.9" ; for star No. 
97, — O05I' 13.2"; for star No. 135, 9° 39' 43.7"; for star No. 147, 24° 50' 18.3"; for star No. 192. 47° 25' 34.7": for star No. 217. 8° 42' 57.9"; tor 
star No. 226, 21° 26' 11.8" ; for star No. 227, 41° 05' 21.4 ; for star No. 229, 24° 07' 23.4" ; for star No. 246, 39° 06' 59.7" ; for star No. 28, 14° 53' 
30" ; for star No. 230, 46° 49' 45". 

Star No. 123 was by mistake used twice at this station in diderent pairs. 



UNITED STATES AND MEXICAN BOUNDARY. 



101 



The computations of the latitude were made by the formulse and tables given in the Coast 
and Geodetic Survey Eeport for 1880, Appendix No. 14, with the exception of certain changes 
noted below. 

The formula for the level correction as there given is intended for a level in which the gradu- 
ations are marked from the middle outward in both directions. The graduation on the level used 
in these observations is numbered coniinnoudy from one end to the other, the zero being nearest 
the eyepiece. If n and s be the north and south reading of the level for the south star, and n' 
and s' the same for the north star, and h the value of one division, then the correction for this 
level is ^- 1 {n'+s')-(n+s). 

The table given in the appendix referred to for the difference of refraction of the two stars of 
a pair is based upou the supposition that the refraction at the station corresponds with sufficient 
accuracy to the mean refraction at sea level. The elevation above sea level at the station occupied 
was great enough in some cases to diminish the refraction by 15 per cent or more. In these 
cases the values given for the differential refraction were diminished in that ratio. 

The latitude from each individual observation being computed, these values were combined 
and the probable errors computed as follows: 

Let N = total number of observations at the station; 
n = number of observations on any pair; 
p = number of pairs; 
J = difference between the latitude from each observation and the mean result for the 

pair; 
^(p = the difference between the result for latitude from any one pair and mean result 

from all pairs ; 
e = the probable error of a single observation ; 
e,j = the probable error of the mean result from a single pair; 
cs = the probable error of the mean of two star declinations; 
e„ = the probable error of the final weighted mean of the pairs; 
tci, w-,, 103 — the weight assigned to the separate pairs; 
Then, 

„ 0.4552^2 , ()A552^cp' , e' 1 22, 

1)—1 J) n * 

the separate paii 



n-2 assigned 
-^ for the respective pairs. 



The weights 
1 



must be pro|)ortional to the (juantities 



^ 2_ 0.155 2 u- Aqj' 
{p~l)2w 
The following table indicates the degree of accuracy attained at each station and the plan 
work as to number of observations and number of jiairs: 



station. 


Number 


Num- 
ber 
pairs. 


^- 


es- 




Total 
range. 


Greatest 
range 


Nun,ber 
obser- 
vatious 
re,iected. 


No 1 


67 
39 
46 

130 
99 

102 
99 

100 

101 

;:: 
121 

105 
25 
96 


19 
39 
46 
19 
50 
57 
63 
75 
72 
76 
92 
93 
.45 
24 
76 


±0.38 


±0.15 


±0.06 
± .07 

± .04 

± .04 
= .04 
± .03 
± .03 
± .04 

± .04 

± .08 
± .04 


3.' 28 
3.29 
2.33 
4.04 
2.04 
2.28 
2.50 
2.02 
2.21 
2.18 
2.08 
3.66 
2.35 
2.30 
2.95 


2.10 


1 


N0.2 










I 


No 4 




.36 

.22 
.20 
.26 
.21 

.21 
.23 
.31 


± .21 
± .24 

::i: 

± .24 
± .25 
± .14 

± .29 
+ .02? 


3.08 
.93 
1.26 
1.76 
.95 
.88 

1.06 
1.45 
1.40 




N0.6 






' 


N0.8 


N0.9 





No. 10 




No. 11 








No. 13 




No.14 




No 15 




.22 


± .32 


1.26 


3 1 




1, 362 




1 








', J 











102 UNITED STATES AND MEXICAN BOUNDARY^ 

Tlie number uf observiitions as given in the table is the number actually used after the 
rejection of erroneous observations, as indicated in the last column. 

At Stations Nos. 2 and 3, where only one observation was taken on each pair, and at Station 
No. 14, where but one pair was observed more than once, the probable error of a single observation 
can not be computed by the formula given above. In those cases the ordinary formula- for inde- 
pendent observations of equal weight were used to compute the probable error of the result for 
latitude from any one pair (including both errors of observation and of declination). The probable 
error of the latitude from a single pair observed once as thus derived is for Station No. 2, ± 0.44" ; 
for Station No. 3, ± 0.3.5", and for Station No. 14, ± 0.38", 

The computed value for the probable error of a single observation depends only upon obser- 
vations on pairs which were observed more than once. For Stations No. 5 to No. 12, and No. 15, 
it therefore depends upon but a small portion of the observations. As the computed i)robable 
error of declination, however, depends upon the difference between e^' (computed from all the 
observations) and e-, too small a value for e will give too large a value for eg, and vice versa. For 
this reason the two columns giving c and cs should both be considered in judging of the accuracy 
of the observation. 

At Station No. 4 the formulie gave for c ± 0.36" and for Cs ± 0.09". This value for e^ is 
evidently much too small. Instead of assigning weights according to these values of the probable 
errors all pairs were given equal Avcight, each pair being observed either six or seven times. 
On the ttrst night of observation and during the early part of the second night the wind was 
blowing in through the slit in the observatory roof in jnifs; the latitude level showec" rapid 
changes of inclination of the vertical axis, and the residuals indicate a less accuracy than usaal. 

At Station No. 13 the formula- gave for c i 0.28" and for e^ ± 0.02". This computed valc^^ of 
d being evidently much smaller than the reality, the different pairs were given weights on the 
assumi>tion that in fact e = 0.9 c. 

Most of the observations were made under meteorological conditions very favorable to accui ?ite 
observation. The typical working night was perfectly clear, with no strong winds, and with air 
so dry that no dew fell even during the cool morning hours. Under such conditions the st?Ts, 
except near sunset, showed very brightly and with little or no twinkling or dancing as seen reith 
the telescope. 

The door of the observatory tent was kept open and the circulation of air through tlaor, 
sides, roof, and door of the tent usually kept the temperature inside the tent within less than a 
degree centigrade of the temperature outside. This seemed to be an important factor in control- 
ling the apparent steadiness of the stars; for at Nogales in a wooden building and at Yuma in an 
adobe building, with the outside meteorological conditions just as favorable as before, there was 
a much greater difference between the inside and outside temiierature, and the stars showed a 
marked unsteadiness as compared with their usual appearance. 

The value of micrometer was determined at every station save No. 14. In each case, except 
at Station No. 11, ti-ansits across the thread of Polaris near elongation were observed, the 
thread being set at each half-turn in succession for the twenty turns nearest the middle of the 
field of the telescope and the time of transit observed by eye and ear. At Station No. 11 similar 
observations were made upon A UrsiB Minoris. 

The value of micrometer was computed from these observations by the formula- of the 
appendix already referred to. (Coast and Geodetic Survey Report, 1880, Appendix No. 14.) 

During the first set of observations, on February 15, 1892, the quarter-turns were also 
observed on the middle ten turns to detect periodic error in screw value. The values of the four 
quarter-turns as derived separately agreed with each other within the respective probable errors, 
and thus gave a nil result. 



UNITED STATES AND MEXICAN BOUNDARY. 
Summary of mkrtuntltr (leteiminaliiiiis. 



103 



station. 


Date. 


Value of 
turn. 


Probable 
error of 

turn. 


Temper- 

dnring 
observa- 
tion. 


No 1 
No I 


Fell 15 1892 
1 (-1. 19 1892 


62.227 
62. 107 


±0.008 
i; .010 


° 


9 


No 1 


Feb J7 1892 


62. 223 


± .012 


10 


No 3 


Mir 23 1892 62.163 


± .014 


12 


No 3* 


Apr 10 1892 1 62.118 


± .008 


26 


No 4 


M>r 22 1892 62. 105 


t .006 


7 


No 5 


Maj 30 1892 62.093 


± .008 


16 


No 6 


Juuo21 1892 62.101 


± .017 


26 


No 7 


JuU 26 1892 62.078 


± .009 


19 


No 8 


Vug 15 1892 62. 099 


i .017 


23 


Nc 9 


Sei.t 7 1892 


62.164 


+ .010 


23 


No 10 


(Jet 4 1892 


62.016 


± .011 


24 


No 11 


Nov 8 1892 


62.025 


± .016 


■2 


No 12 


Nov 25 1892 


61.898 


± .014 


8 


No 13 


Jan 25 1893 


61.994 


± .031 


10 


No 15 


Si.pt 25 1893 


62. 059 


i.009 


16 



* Illumination from aky only. 

The observed microaietei- value apparently is not a function of the temperature at the time of 
observation. 

The latitude at Station No. 1 was computed with the value of one turn=62.225", the mean 
of the observations of February 15 and 27, rejecting the observation on February 19. The value 
of one turn as derived from the latitude observations at the station is G2.207". 

At Stations No. 2 to No. 10, and No. 15, the value of micrometer as observed at the station 
and shown above was used in computing the latitude. 

The mean of the first twelve values of one turn in the above table is 62,124". At Station No. 
11 the latitude observations, when reduced with the value, 02.025", as observed at that station, 
showed a total range of 3.85", apparently systematic with reference to micrometer difl'erence.s. 
The micrometer value was then derived from the latitude observations and found to be 62.123". 
As this corresponded very closely with the mean value given above, the observed value at the 
station was rejected and the observations reduced with said mean value, 62.124". The total 
range in the results for latitude as thus computed was 2.08". 

At Station No, 12 the values for the latitude showed an abnormal range when reduced with 
the value of micrometer as observed at the station, namely, 61,898". The value was then deduced 
from the latitude observations and found to be 62.086". The flual latitude computation was made 
with the meau value mentioned above, 62.124". 

At Station No. 13 a similar condition of afl'airs was again found. The latitude observations, 
as reduced with the value of micrometer observed at the station, 61.994", showed a range of 4.10". 
The micrometer value, as deduced from the latitude observations, was 62.120". The final latitude 
computation, as made with the mean value, 62.124", showed a total range of results of 2.35" only. 

No adequate explanation was found for the apparently erroneous observations of micrometer 
value at Stations No. 11 and No. 12. At Station No. 13 the observations were taken in an adobe 
building; the temperature was remarkably difiereut inside and outside; the line of sight passed 
through a comparatively small hole in the wall; the apparent motion of the star was unsteady 
and the computed probable error of the result is two or three times as large as for similar 
observations at other stations. 

The micrometer value was deduced from the latitude observations in the cases mentioned 
above, as follows: Let cp be the mean latitude (as deduced with an approximate micrometer 
value), from pairs on which the micrometer difference (S-N) was positive, qj2 the mean latitude 
from pairs with minus micrometer diii'erence, D, the mean of plus micrometer differences, and D^ 
the mean of minus micrometer differences. Then the correction to the approximate value for one 



turn of micrometer is 



2(cfH-<Pj) 



104 UNITED STATES AND MEXICAN BOUNDARY. 

The effect on the computed latitude of an error, m, iu the assumed value of one turn of 

micrometer may be estimated as follows: Let <Z„ <?2, d^, be the micrometer dift'erences, and 

toi, Wj, W:i, the assigned weights of the resjiective pairs Then the computed value of the 

altitude will be iu error by -^^^.vi 

This is upon the assumption that the actual value of micrometer remains sensibly constant 
during the stay at any one station. The focal adjustments were never changed at a station after 
they were made at the beginning of the first night's observations. An increase of temperature 
lengthens the barrel of the telescope and also lengthens the micrometer screw. The first change 
decreases the micrometer value and the second increases it. The combined effect is to change the 
micrometer value by a very small amount, depending upon the difference of the coefficients of 
expansion of the brass telescope barrel and the steel screw. The other effects of temperature are 
difttcult to predict. 

At each station the value .,^,- was made as small as was conveniently possible. The «c^)m(/ 

observed micrometer differences multiplied by approximate weights were summed for each night, 
and the list for the last night so chosen as to make the sum for the station nearly zero. The 

values of g^^,*,, for the separate stations are: At Xo. 1, -0.10; at No. 2, +0.03; at No. 3, +0.18; 

at No. 4, -0.01; at No. 5, +0.06; at No. G, -0.02; at No. 7, -O.IG; at No. 8, +0.02; at No. 9, -0.17; 
at No. 10, -0.18; at No. 11, +0.36: at No. 12, -0.06; at No. 13, +0.02; at No. U, -0.08; and at 
No. 15, —0.04, It is ijrobable that the error of latitude from this cause is not greater than 0.01" 
at any of the fifteen stations. An error in the assumed micrometer value tends, by increasing the 
range of results, to make the computed probable error of the final result for latitude greater than 
it actually is, provided the micrometer differences nearly balance. 

The levels furnished with the zenith telescope were tested with a Coast and Geodetic Survey 
level trier under favorable conditions at the Coast and Geodetic Survey Oflice at Washington, 
D. C, in January, 1892. The mean values from the observations are: 

Level marked "20a", with Wurdeiuauu zenith telescope, No. 20, one division ^1.04" 
Level marked "206", with Wurdeniann zenith telescope, No. 20, one division ^1.28 
Level marked "19a", with Wurdemaun zenith telescope, No. 19, one division =1.45 
Level marked "19')", with Wurdemiinn zenith telescope. No. 19, one division :=2.08 

The greatest variation in the value of one division in any of these tests was 0.06" from tlie 
mean. Level " 20a " carries 1 min. graduations and the others 2 mm. graduations. 

Level "20?»," one division = 1.28", was used during all the latitude observations. A test of 
this level by intervals of about two divisions showed it to be sensibly regular, even to the extreme 
ends. The bubble moves with a remarkably smooth motion. 

At Station No. 1 the average level correction is about +0.5 division. The assumed value of 
one division may be in error by as much as 0.04", and therefore the computed latitude may be in 
error 0.02" from this cause. At all the remaining stations the instrument was releveled as soon 
as the level correction became as much as one division. No difficulty was found in keeping almost 
all the level corrections within this limit, and the average level correction at each station is but a 
small fraction of a division. At these stations the error iu latitude arising from error in level 
value is probably not greater than 0.01". 

The uniform practice was for the recorder to call out the chronometer time of transit of the 
star across the meridian for every star observed. This enabled the observer to detect any motion 
of the telescope in azimuth and to keep it so nearly in the meridian at all times as to prevent any 
sensible errors from that cause. 

But one of the three horizontal threads was ever used for latitude observations. That one 
was adjusted before beginning ob.servatious at each station so as to be so nearly horizontal that a 
series of pointings on a star passing through the field when the telescope was in the meridian all 
agreed within the hour of pointing. This adjustment was sometimes found slightly disturbed 
after transportation, but usually remained perfect. 

The star was bisected as soon as it reached the safe portion of the eyepiece field and kept 
bisected until it reached the meridian. 



The probable error of a single observation = e = J '^ 



UNITED STATES AND MEXICAN BOUNDARY. 105 

The wooden pier used as a support for the zenith telescope proved to be as stable as a masonry 
pier. The instrument, after having been leveled, usually remained for two or three hours with its 
vertical axis so nearly vertical that the level correction was less than one division (1.28"). 

It was not uncommon for the level correction to remain without releveling less than one division 
during the whole of a night's work, even in cases in which the observations extended through 
nearly all the hours of darkness. When using the wooden piir the observations for a night 
usually show a very slow motion of the vertical axis of the instrument so as to incline more and 
more to the southward, as if the southern side of the pier were gradually becoming shorter 
relatively to the northern side. This motion was exceedingly slow; so slow that, as stated above 
the level correction usually remained less than one division for hours at a time without releveling. 

To obtain an additional check ou the degree of accuracy of the star places and of the observ- 
ing, advantage may be taken of the fact that ou each of the parallels the same pairs were observed 
at sereral stations. Each observation may be considered as a determination of the correction to 
the mean declination of the two stars observed. 

Let E — Final mean hititude of station minus the latitude from any one observation ; 

Then JS = Most probable correction to the mean declination for the i)air; 

= Mean value of R for that pair from all observations at all stations; 

Let »• ^B—JS. 

Let N be the total number of observations at the series of stations treated as a single group; 
P the total number of pairs observed, and n the total number of observations on any one pair at 
all the stations. 

.455 ^'r^ 
P 

By the same process of reasoning as is employed in separating errors of observation and of 
declination in the latitude at a single station there is obtained : 

Ca = the probable error of the mean declinatiou for a pair; 

^jEfrWiu which E-^=^^^ and E^ ='^^1 

The above formula' i)resupposes that the several determinations of the declination correction 
to i\. pair made at any one station are independent, which they are not, inasmuch as they involve a 
common error— the error of the mean latitude for the station; but this inaccuracy of the formulae 
is hardly appreciable for the series of stations in question. 

An error of declination which is constant for the whole list of stars nsed will not, of course, be 
detected by this method. 

For the parallel 31° 47', 272 observations at Stations Xo. 1 to Xo. 4 on 40 pairs, all from 
Professor Saftbrd's list, treated by the above formul;^ give for the probable error of a single obser- 
vation e= ±0.35", and for the probable error of the mean of two declinations es = ± 0.20". 
This value for e agrees quite closely with that derived from the latitude computations for each 
station, namely, ± 0.38" at No. 1 and i 0.30" at Xo. 4. The latitude computation gave for e^ at 
these stations ± 0.15" and ± 0.00", considerably smaller values than that given by the group of 
stations. The probable errors for the separate stars, as stated in Professor Safiford's list, gives for 
es i 0.18". Of the derived corrections JS to the mean declination for a pair the greatest was 
± 1.02"; but 9 of the 40 exceeded 0.50" and 19 were less than 0.20". 

At Stations Xo. 5 to Xo. 12, on the parallel 31° 20', 819 observations on 183 pairs, all from 
Professor Saftbrd's list, gave for e ± 0.28" and for e^ =1= 0.17". For the same stations the mean 
results from the latitude computations were e = ± 0.23" and ''(^ = ± 0.22". The probable errors 
of declination for the separate stars as given in Professor Saftbrd's list would make es for these 
stars ± 0.17", in agreement with the result from the group of stations. 

Of the 183 corrections, Jcf in this group the greatest was — 1.10"; but 23 exceeded 0.50" 
and 80 were less than 0.20". 

The indications given by these two computations are that the probable error of a single 
observation as derived from the latitude computations is slightly too small and that the accidental 
errors in the star places are about as indicated by the probable errors given in Professor Saftbrd's 
star list. 

S. Doc. 247 11 



106 UNITED STATES AND MEXICAN BOUNDARY. 

At several stations a portion of the observations were talien on stars t'rotii Professor Sattbrd's 
list and a few sui)plemeutary pairs were chosen from the American Ephemeris, the Berliner 
Jahrbuch, and Preston's Hawaiian list. That there is no sensible common error in either of these 
lists not common to all is put in evidence by the agreement between the latitude as derived from 
Safford pairs exclusively or from supplementary pairs alone. 

Latitude of Station No. 3. from all observations, 46 pairs = 31 46 58. 00 i 0. 05 

Latitude of Station No. 3, from Saft'ord pairs only, 36 pairs = .57. 98 j- 0. 06 

Latitude of Station No. 3, from supplementary pairs, 10 pairs = 58. 04 -{- 0. 11 

Latitude of Station No. 5, from all ob.servations,. 50 pairs =31 20 02. 00 ±0.04 

Latitude of Station No. 5, from Safford pairs only, 47 pairs = 02. 01 ± 0. 04 

Latitude of Station No. 5, from supplementary pairs, 3 pairs = 01. 86 ± 0. 15 

Latitude of Station No. 6, from all observations, ,57 pairs = 31 19 57. 94 J- 0. 04 

Latitude of Station No. 6, from Safford pairs only, 47 pairs = 57. 95 J; 0. 04 

Latitude of Station No. 6, from supplementary pairs, 10 pairs = 57. 91 ^ 0. 09 

Latitude of Station No. 7, from all observations, 63 pairs = 31 19 56. 73 -|- 0. 04 

Latitude of Station No. 7, from Safford pairs only, 50 i)air8 = 56. 77 J- 0. 04 

Latitude of Station No. 7, from supplementary pairs, 13 pairs = 56. 54 -J- 0. 08 

At Stations No. 14 and No. 1.5, a Safford star being used in many cases with a star from some 
other list to form a pair, such a test as that given above can not be made. At Stations No. 1, 
No. 2, No. 4, and No. 8 to No. 13 only Safford stars were used. 

As the general plan of observation adopted at most of tlie stations of this survey differs 
materially in one important respect from tliat usually followed, it is pertinent here to point out the 
rea.sons which led to the change from usual practice and to note how the results have ju.stifled 
the change. 

The ordinary procedure at a lirstclass zenith telescope latitude station is to observe the 
same list of about 20 pairs on from four to seven nights. That plan was followed at Stations 
No. 1 and No. 4. Starting witli the premise that the prime object of latitude observations is to 
secure with a minimum expenditure of time and money a result for latitude having a given 
probable error, say ± O.O.j" or less, a study of the relative magnitude of the errors arising from 
various sources and the cost of reducing these errors led to the conclusion that the number of 
independent pairs observed .should b^ greatly increased relatively to the number of observations. 
It seemed that the greatest accuracy for a given amount of money would be secured by ob.serving 
each pair but once, or at most twice. Accordingly the method of securing as many independent 
pairs as possible was followed at all stations except No. 1 and No. 4. The results of this procedure 
serve as its best champion. 

A simple comparison of the probable errors of the final results at Stations No. 1 and No. 4 
with the corresponding probable errors at later stations is not fair to the old plan of work; for at 
those stations unfavorable conditions, namely, inexperience of observer at No. 1 and bad meteor- 
ological conditions at No. 4, made the probable error of observation at tho.se stations greater than 
foi' any succeeding station. 

At Stations No. 2 and No. 3, however, the probable error of a single observation was about the 
same as at No. 1, and a comparison is just. At No. 2 and No. 3, 39 and 46 observations respec- 
tively, no pair being observed more than once, gave about the same degree of accuracy in the final 
result as 67 observations at No. 1. 

At Stations No. .'» to No. 12, wliere the plan of work was inost uniform, from !»9 to 120 obser- 
vations were taken at each station on from .50 to 93 pairs, no pair being observed more than 
twice. 

Tlie probable error of the final result for each of these stations is either ±0.04" or ±0.03". 
Taking the average values at the.se eight stations for the number of observations and number of 
pairs, for e and e^ there is obtained as a typical station 108 observations on 72 pairs with 
e-i: 0.23" andej = ± 0.22". (See table, page 180.) 



UNITED STATES AND MEXICAN BOUNDARY. 107 

For this typical station the probable error of the result is 

V *108 '■*■ *^7?^'= V{0M2Y-H(>^W= i 0.034". 
If the same number of observations were taken upon 18 pairs, 6 observations per pair, c and 
e3 remaining- the same, the probable error of the final result would be 



v 



(0.23V- (0.22V' 

108+18^ ^ ■v/(0.022)^'+ (0.052)^= ± 0.056" 



An injiuitc number of observations on 18 such pairs would give a result with a probable error 

0.22 
of y-~- = zl= 0.052", that being the error from declination alone. Even if the probable error of a 

single observation were twice as great as in the actual case, namely, ±0.46", and d were ± 0.22" 
as before, 108 observations oa 72 pairs would give a result with a probable error of 



V 'w" + '"7?''= a/(O.OM)H (0.026)-'= ± 0.031" 

a more accurate result than could possibly be obtained from only 18 such pairs observed any 
number of times with any degree of accuracy. 

In cases in which the accuracy of the available star places is not as great as for the list here 
used there is still greater advantage in the method of observing a large number of pairs. 

This method of work involves the necessity of computing a greater number of mean star 
places than usual; but the cost of that part of the work is but a small portion of the total cost. 
A considerable portion of this list would have been needed even if the ordinary plan of work had 
been followed. 

An accidental, but important, advantage of the method of observing many pairs is the way 
in which partially cloudy nights and isolated clear nights in the midst of a cloudy season may be 
utilized. If one is observing in the ordinary way on a list of, say, twenty pairs, only about three or 
four hours of a perfectly clear night can be utilized, even though there may be great anxiety to 
finish the work at the station. On the otlier hand, the observations are entirely prevented for the 
night if it is cloudy during the three or four hours covered by the limited list, and the whole night 
is lost even though it may be clear during the greater portion of the time. 

At Stations jSfo. 5 to Xo. 12 and No. 15 the available pairs formed a double (and in some cases 
even a triple) list extending through most or all of the available hours of darkness. At these 
stations there was not the slightest difficulty in utilizing partially cloudy nights, or in utilizing all 
the hours of darkness on clear nights when there was a necessity for rapid work. At Station No. 
6, 49 and 4S observations, respectively, were taken on the nights of June 14 and 16, thus nearly 
tinishing the work of the station in two nights. At Station No. 15 the observations were greatly 
delayed by clouds. When the weather at last cleared, 72 observations were taken on the nights 
of September .30 and October 1, and the work at the station finished on tlie 2d by 22 obser- 
vations. 

Taking most or all of the observations for a station on one, two, or three nights will decrease 
the accuracy of the result if there are constant errors peculinr to each nif/ht, but not otherwise. 

The results, as classified by nights and given below, serve to show that for this series of 
observations the discrepancies between the results for different nights are no greater than should 
be expected from the accidental errors of observation and declination. 

The column headed '-Residual" shows the difference between the result for the night and the 
mean for the station. The column headed "Co (observations oidy)" shows the probable error of 
the mean result for the night as arising from errors of observation only, neglecting the declination 
error, or, in other words, the probable error of a single observation divided by the square root of 
the number of observations on the night in question. 



108 



UNITED STATES AND MEXICAN BOUNDARY. 



::\ 



Apr 2) 



59.40 
.59. 39 
59.37 



only). 



Ji.m lb 
luiii 21 
7uh 7 
Jllh 8 
Juh '1 
Jllh il 
Juh J6 
Juh 27 
Jul} 28 
Aug 'I 



57.95 
58.13 
56.68 
56.68 
66.77 
56.58 
56.86 
56.81 
56.62 
59.05 
58.93 



S<i>t 10 


22 


S.97 


b.i.< 12 ; 


20 


0.12 


Sipt 11 


34 


0.08 


Oit 1 , 


18 


34.96 


Oct 4| 


21 


34.73 



57. 49 
.57. 34 
57.32 
57.32 



Feb 16 
I Sept 27 ' 
Sppt 30 I 



.14 i 



UNITED STATES AND MEXICAN BOUNDARY. 10!) 

The mean value of tlie residuals, or differences between the result for the niyht and the mean 
for the station, is 0.09". On 31 nights, out of a total of CS, the residual was not greater than the 
probable error in the result arising from observatiou only. 

TBI ANGULATION. 

The triangulatiou near El Paso was intended merely to connect Astronomical Station No. 1 
with Emory Monuments No. 1, No. 2, and No. 3, but was extended to couuect with j)rominent 
buildings in El Paso and Juarez, and with the triangulation of the Coast and Geodetic Survey 
longitude party at K\ Paso in 1892. The measurements of base and angles were made conjointly 
by the tangent party under Mr. E. L. Ingram, assistant engineer, and the astronomical party. 

A base 5.50 feet long w as measured with 20 m. and 50 m. steel tapes on the railroad track near 
the astrononncal station. During the measurement the tape was placed upon the rail and was 
therefore supported throughout its whole length. The temperature of the rail, as ret'orded by a 
thermometer placed against it, was assumed to be the same as the tem[)erature of the tape. The 
lengths of the tapes used in this and later base measurements were determined in January, 1892, 
on the mural standard of the United States Weights and Measures Office at Washington, I). C. 
The lengths were determined with the tapes supported throughout their whole length. Three 
double measures of the base, each forward and back, using two different tapes and on two dates, 
by difterent men, gave a range of 0.021 m. 

The horizontal angles were measured with three different instruments — Wurdemann S-inch 
repeating theodolite No. 85, Coast and Geodetic Survey 8-inch repeating theodolite No. 149, and 
Fauth theodolite No. 725 (described as the instrument used for azimuth). The observations were 
made upon poles at convenient hours of the day, the observing not being confined to the hours of 
steady seeing. The instrument was usually mounted on its trij)od and was unprotected front sun 
and wind. 

The sketch of the triangulation shows which stations were occupied. The average closing 
error of the triangles was 15.3" and the greatest closing error 20.4". 

The azimuths and geographical positions given depend upon the observed azimuth and lati- 
tude at Astronomical Station No. 1 and the longitude observed by the Coast and Geodetic Survey 
in El Paso in 1892. 

The tables of geographical positions are given in Chapter IN' of United States liei)ort. 

The astronomical station was marked by a stone weighing about 250 ])ouii(ls, having a lead 
plug in the top and sunk just below the surface of the sand. 

North Base and South Base were marked by stakes about 07 mm. s(|uarf. driven neaily down 
to the surface. 

The station on the Federal building is the flagstaff at tlie northwest corner of the tower. 

The station on the court house is the flagstaff on the dome. 

The station on the cathedral at Juarez is the large cross. 

Stations A, B, and C are marked by wooden stakes. 

At San Pedro River the triangulation consisted of a single quadrilateral, of which one 
diagonal was the measured base and the other a line joining Astronomical Station No. 10 with 
a point called A, near Monument No. 98. This quadrilateral served to connect the astronomical 
•station with the monument and with the tangent to the westward, which begins at A. All four 
stations were occupied and the closing errors of the three principal triangles of the figure were 
8.4", 0.6", and 0.2". The observations were made with Coast and Geodetic Survey theodolite 
No. 149 and with Fauth theodolite No. 725. 

The base, 484 m, long, was measured with a 50 m. tape, supported by the ground throughout 
its length. Four measurements giving a range of 0.024 m. were made just before and after sunset. 
The temperature of the tape was assumed to be the same as that recorded by a thermometer 
lying on the ground. 

The observed latitude of Astronomical Station No. 10 is 31° 19' 34.84"; and the azimuth of the 
line to A, 12.5° 21' 0.8", (back azimuth = 305° 20' 35.1"). The distance to A was 1,601.3 ni. Tlie 
latitude of A is 31° 20' 04.92", and its longitude 0"^ 00' 49.40" west of Astronomical Station No. 10. 



110 UNITED STATES AND MEXICAN BOUNDARY. 

Monument No. 98, 8.1 m. west and 7.7 m. south of A, is in latitude 31° 20' 04.67". 

The astronomical station and Station A are marlied by pine stakes about 65 mm. square. 

The triangulation at Nogales served to connect the latitude, longitude, and azimuth stations 
with prominent points in the town, with Monuments No. 12ii and No. 127, and with the instru- 
mental line which afterwards connected Monument No. 127 with Monument No. 204 at the Colorado 
liiver. 

The base, 725 m. long, was measured between the rails of the railroad track just south ot 
town, at night, with a 50 m. steel tape. The tape was supported throu{;hout its whole length by 
the ties and ballast. The position of the end of the tape for each tape length was marked with 
an awl on a zinc plate previously placed in position on a tie or on the head of a stake driven flush 
with the surface. The temperature was recorded by a thermometer placed on the ballast near the 
tape. Three measurements gave a range of 0.005 m. 

The angles were measured with Fauth direction theodolites No. 433 and No. 813. These are 
twin instruments, the only marked difference being in the style of finish. The horizontal circles, 
20 cm. (S inches) in diameter, are graduated in ten-minute spaces and every degree is numbered. 
The circle is read by two opposite micrometer microscopes. Each half-turn of micrometer head 
corresponds to 1 minute on the circle and is graduated to thifty divisions (2 seconds each). Hence 
the sum of the forward and back readings on the head gives the number of seconds of the reading 
of the circle, except for error of run. The standard or yoke of the instrument is quite low and the 
telescope will not transit. 

The observations were made at convenient hours of the day, not being confined to the short 
hours of steady seeing. As a rule the observations at a station were completed on the first day it 
was occupied. Poles were used as signals. The instrument was usually supported simply on its 
tripod, and was not protected from the sun or wind. 

The routine of observation, as is usual with a direction instrument, consisted of a pointing 
and reading of horizontal circle for each signal in turn from left to right, and then back again in 
the contrary order after reversing the telescope. Five positions of the circle, 72° apart, were 
used. Tlie minimum of observation at a station was one set in each position of the circle, and as 
a rule the number of sets was between five and ten. 

The greatest range in the different measurements of any one direction was 21.8" and the mean 
range 11.8". One triangle had a closing error of 18.9", and all the others closed within 10". The 
mean closing error was 5.3". 

Tlie azimuths depend u])on the observed azimuth of the line, azimuth station to azimuth 
mark; the latitudes upon the observations at Station No. 12, and the longitudes upon the obser- 
vations at Station No. 12, by the Coast and Geodetic Survey in 1892. 

The tables of geographical positions are given in Chapter IV of United States Report. 

The point called "Astronomical Station No. 12 (observing stand)" in the list is tlie center of 
the tripod, which was built just outside the observatory to support the instrument when measuring 
horizontal angles. It is 2.22 m. south and 1.28 m. east of the latitude pier and due south of the 
longitude pier. The latitude of the piers is 31° 20' 4.77". These piers of brick and cement were 
left standing, inclosed in a small wooden observatory in the grounds at the rear of the Montezuma 
Hotel. 

The reference marks at each station were, unless otherwise stated, placed approximately 
north, east, south, and west from the station mark, and the monuments gi\ en below are from the 
station mark to each reference. 

Azimuth station, station marlc 2incli by 4-iuch pine slake, references 1-inch by 1 -inch i)ine 
stakes, N. 0.831 m., S. 1.025 m., W. 0.844 m., E. 0.989 m. 

North Base is in the switch yard of the Sonora liailroad, on the prolongation of the center 
line of the track on last tangent before entering the yard from the south; station and references, 
2 inch by 4inch pine stakes, N. 0.975 m., S. 1.077 m., W. 0.899 m. 

South Base is 9..58 m. eastward from the center line of the Sonora Railroad track; station and 
references, 2-inch by 4-inch pine stakes, N. 0.765 m., E. 0.845 m., W. 0.7.!4 m. 

No. 1, station 2-inch by 4-inch pine stake: references, flve-eighths-inch iron rods, N. 1.082 m., 
E. 1.182 m., S. 1.182 m., W. 1.220 m. 



UNITED STATES AND MEXICAN BOUNDARY. Ill 

No. 2, stalion and leferences, five-eightlis-indi iron lods, N. 1.088 m., E. 0.971 ni., S. 0.91.'.) in., 
W. 0.926 m. 

No. 3, station and references, five-eightlis inch iron rods, N. 1.140 ni., E. 1.080 m., S. 0.9G6 m., 
W. 1.110 m. 

No. 1, station and references, five-eightli.s iucli iron rod.s, N. 0.972 ni., E. 0.976 m., S. 1.017 ni., 
W. 1.070 m. 

No. 5, station -l-iuch by 4-inch ])ine stake; references, 2-inch hy 2incli ])ine stakes, N. 1.008 ni., 
E. 1.171 ui., S. 1.102 III., W. I.(t4] in. 

No. 6, station and references, five-eighths-iuch iron rods, N. 1.140 in., E. 1.113 ui., S. 1.128 in., 
W. 1.225 m. 

No. 7, station and references, tive-eighths-iuch iron rods, N. 1.00") ni., K. 0.930 in., S. 1.000 in., 
W. 1.152 m. 

No. 8, station mark five eighths-inch iron rod; reference, NW. to nail in stuiiip 1.254 in., SE. 
to nail in tree 3.757 m., S W. to nail in tree 6.570 m. 

B, 4.76 m. south and 4.11 in. west of Emory Monument XIX, station five eighths inch iron 
rod, reference nails in trees, N. 6.431 m., E. 2.827 m., S. .5.159 m., W. 3.G.34 in. 

The astronomical party also ran a tangent to the prime vertical at the azimuth station west- 
ward to a point near Monument No. 127, and determined by intersections from triangnlatiou 
stations the distances to ten points on the tangent, for the use of the topographical party and the 
monument party. 

As a check upon the accuracy of the triangnlatiou it may be mentioned that the azimuth of 
the line azimutli station to B, as given by the latitudes and longitudes of those stations computed 
through the wliole triangulation, was 90^ 29' 0.6", while a direct measurement at the azimnth 
station of the angle between B and the azimuth mark gave for the same line x = 90° 29' 2.7", a 
difference of 2.1". 

The triangulation near Yuma, Ariz., served to connect Astronomical Stations No. 13 and No. 
14 with each other, with prominent points in Yuma, with Monument No. 207, just west of the 
Colorado River and the instrumental line westward to the Pacific, and with Monument No. 204, 
20 miles below Yuma, and the instrumental line eastward to Nogales. 

The base, 2,205 m. long, was measured on the mesa just south of Yuma with a 50-m. tape at 
night. With the exception of certain fractional tape lengths the line was measured with tlie tape 
supported by the sand throughout its whole length, the very few slight inequalities of the ground 
having been removed. The base was nearly level, with the exception of two tape lengths at the 
east end. Here the line rose to tlie top of a rocky hill about 19 m. above the remainder of the 
base. The ascent was made by two tape lengths on a considerable inclination, the difference of 
height of the different points of support of the tape being measured with a spirit level. The 
position of the end of the tape for each tape length was marked with an awl on a zinc plate on 
the head of a stake driven flush with the surface of the sand. The temperature of the tape was 
assumed to be the same as that recorded by a thermometer placed near the surface of the sand 
near the tape. Two measurements of the base made on the nights of January 28 and 30 under 
very favorable conditions — little or no wind, clouded sky, and nearly constant temperature — 
differed by 0.007 in. 

The angles were measured with Fauth direction theodolites No. 433 and No. 813. The gen 
eral plan of observation was the same as at Nogales. The observations were not limited to the 
hours of steady seeing. Both poles and heliotropes were used as signals. The instrument was 
not protected from sun and wind. At Monument No. 204 a tripod and scaffold about 8 m. high 
was built to jilace tlie instrnment high enough to see over the slight swell of the mesa between 
that point and Yuma. 

As before, five positions of the ciri'le were used. The miniinnm ol' observation at a station was 
one set in each position of the circle, and the actual number of sets was usually between five 
and ten. 

The greatest range in the measurements of any one direction was 17" and the mean range 
7.2". The greatest error of closure of a triangle was 5" and the mean closing error 2.6". 



112 



UNITED STATES AND MEXICAN BOUNDARY. 



The ti'iaugulatioii was adjusted by least squares to satisfy the side and angle conditions. 
The greatest correction to any observed direction from this adjustment was 2.2" and the mean of 
the corrections 0.9". 

The azimuth of the line ^Monument 204- A.zimiith Mark, as computed tlirough the triangnlation 
from the observed azimuth at Yuma is 178° 31' 20". The azimuth of the same line as observed 
at Monument 204 is 178o 31' 21". 

In the table the azimuths and latitudes depend upon the observations at Yuma and the 
longitudes npon the observations at Yuma by the Coast and Geodetic Survey in 1892. 

The tables of geographical positions are given in Chapter IV of United States Report. 

The location of each station will be found upon the published topographical maps. 

The latitude and longitude piers of brick and cement were left standing in the east room of 
tlie adobe building which forms a part of the north wall of the old Government corral in Yuma. 
The brick pier at the azimuth station was left standing. 

B Tangent 10 is marked by a pine stake. 

EastBase, station and references five eighths-inch iron rods, X. 1..'553 m.. E. 1.038 m.. S. 0.(i72 m., 
W. 1.347 m. 

West base, station and references 2-inch by 4 inch pine stakes, N. 2.07S m., E. 1.951 m., S. 
1.76(i m., W. 2.223 m. 

No. 9, station and references 2-inch by 4-inch pine stakes, N. 0.6(;o m., E. 1.512 m., S. 1.010 m., 
W. 1.913 m. 

No. 10, station and references five-eighths-inch iron i-ods, E. 2"^ N. 3.085 m., S. 27° E. 1.971 m., 
\V. 2° S. 2.172 m. (distances measured on slant). 

No. 11 was on (he sand hills west of the Colorado, and the station marks were doubtless blown 
away in a short time. 

MAGNETIC! OBSERVATIONS. 

The observations for magnetic declination at the first twelve astronomical stations were all 
taken with Coast and Geodetic Survey repeating theodolite No. 149. The horizontal circle, 20 cm. 
(8 inches) in diameter, is graduated in five minute spaces and is read to five seconds by two 
opposite verniers. On the top of the telescope was mounted a compass box containing a 
G-inch magnetic needle and carrying compass sights of the usual form. No iron or steel was used 
in tlie construction of this instrument or its tripod. 



Astronomicul 
station. 


Dat«8. 


Magnetic 
declination 

(K.«fN.) 




1892 


No. 1 


Jtb 20 I'.h 22 M.ir 12 


11 53 


No. 2 


Mir 23 26 28 29 A|,. 2 


10 IC 


No. 3. 


A,,rl) 


11 5(i 


No. 4 


Vpi 30 Ma\ 2 i 


12 00 


No. 5 


June 2 1 4 


12 03 


No. 8 


June 27 


U .-.4 


No. 7 


Tul\ 7 12 20 2- 


12 14 


No. s 


All^ lo Ih 1') 


11 57 


No. !) 


Si,I)t 2 17 


12 23 


No. 10 


Oct 20 


12 19 


No.U 


^o\ 12 15 


12 06 


No. 12 


])oc 12 n 

1 


12 25 



UNITED STATES AND MEXICAN BOrNDARY. 113 

CIL\JPTEK IV. 



The geodetic operations executed by the United States section of tlie commission were as 
follows: 

I. Tracing parallels 31° 47' and 31^ 20' bj' means of tangents to tlie prime vertical at the 
point of beginning and offsets from the same. 

II. Tracing the meridian section by simple alignment, its direction having been previously 
verified. 

III. Tracing the azimuth lines, either by straight lines connecting accepted existing old 
monuments or by offsets from auxiliary lines dittering as little as practicable from tliese lines. 

IV. Triangulation made in the vicinity of the initial monument on the liio (Grande to refer 
this monument to the United States astronomical observatory and to prominent public buildings 
in El Paso, Tex., and Giudad Juarez, Mexico. 

V. Triangulation made in the vicinity of Nogales, to refer Monument 127, at the west end of 
parallel 31° 20', to the United States astronomical observatory in Xogales, Ariz. 

VI. Triangulation made in the vicinity of Yuma, Ariz., to refer Monuments 204 and 207 to 
the United States astronomical observatory in Yuma. 

The geodetic constants conform to Clark's 1860 Spheroid. The principal constants which 
enter into the formuhv adopted are as follows: 

Miijor semiaxia = a = 6,378,206.4 meters. 

Minor seraiaxis = 6 =6,356,58.3.8 meters. 

a' — b- 
Eccentrioity = —.— = .- ^- 0.(K)6768658. 

a:b:: 294.98 : 293.98. 

Radius of sphere with volume of Clarlv's 186(i Spheroid =(>,370,9!»1 meters. 

Radius of sphere with surface of Clark's 1866 spheroid = 6„'>70,997 meters. 

Length of meridian quadrant = 10,001,887 meters. 

1 meter = 3.2808693 feet = 39.3704316 inches. 

1 kilometer = 0.6213768 statute mile. 

1 foot = 0.30479727 meter. 

1 statute mile = 1,609..3296 meters. 

TT = 3.14159265. 

Before entering into a description of the methods employed in tracing the different sections of 
the boundary line, it is necessary to explain M'hat is meant by a "straight line," since, as shown at 
the beginning of the chapter, every portion of the boundary line as marked was traced either by 
the aid of auxiliary straight lines or by straight lines joining consecutive old monuments. 

The theoretical straight line joining two points on the surface of the earth lies in the plane 
which passes through both points and the center of the earth, and if traced would mark the inter- 
section of this plane with the surface of the earth. 

Owing, however, to local deflections of the jilumb line, it is ])ractically impossible to trace this 
theoretical line, but a number of so called straight lines, differing but little from one another and 
from the theoretical line, can be traced, the particular line obtained in each case being dependent 
both upon the method employed and the locations of the instrument stations. 

For example: If two points, A and B, are visible from one another and from intermediate 
points, and if, as is almost invariably the case, local deflections of the plumb line exist at both A 
and B and also at intermediate points, a number of ditterent lines, apparently straight, may be 
run joining A and B, thus: (1) If the instrument remains at A and the foresight at B and inter- 
mediate points are "lined in," a certain line will be traced; (2) again, if the foresight at B remains 
flxed but the instrument is moved up successively to each intermediate point as established, a 
second and different line will be obtained; (3) if the backsight at A remains flxed and inter- 
mediate points are successively established by the method of reversals, the instrument in each 
case being moved up to the point last established, yet another line will be obtained; (4) if the 



114 T-NlTi:i) STATES AND MEXK'AN BOUNDAKY. 

iutermcdiate points are located by the method of reversals, the iiistniiiieiit being moved up as in 
the last case and the backsight established at the next preceding point, a fonrth line will result; 
(5) if both foi-esight at B and backsight at A remain fixed, and intermediate points are established 
by "lining in" the instrument, a fifth line will be traced. 

Now, if exactly the same methods are followed, working in an opposite direction (B toward A), 
five additional lines will be obtained, and by a combination of the preceding methods a still 
greater number of lines will result, all differing slightly from one another and from the theoretical 
straight line sought. 

Computations having shown that for the distances to be encountered on this survey, and for 
ordinary local differences of deflection of the plumb line, lines accurately traced by any one of the 
preceding methods would be sufficiently accurate, all of them were used at one time or another, 
as found most convenient. In general, however, a combination of the first and second methods 
was employed as being quite expeditious, and dispensing with the necessity of a backsight. 

The instruments used in tracing straight lines were Fauth repeating theodolite No. 725, with 
10-inch horizontal circle graduated to 5-minute spaces and read by two opposite verniers to 5 
seconds, and Wiirdemann repeating theodolite No. 85 of the pillar pattern, with 8 inch horizontal 
circle. 

At the commencement of operations wooden targets about 3 feet scjuare, mounted on tripods, 
and similar to those described on page Mo of the report of the survey of the " Northern Boundary 
of the United States from the Lake of the Woods to the Summit of the llocky Mountains," were 
tried, but owing to the fact that during the greater part of the day they were seldom visible more 
than .'5 miles, and to the further fact that, due to the constant winds to which they oi)posed so 
large a surface, they were continually displaced, the use of these targets was soon abandoned and 
heliotropes were substituted for them with results entirely satisfactory. 

These heliotropes were rather crude affairs, with mirrors of 3 and 4 inches diameter, and were 
unprovided with any means for imparting a uniform slow motion to the mirrors. At first the 
mirrors were so mounted on their tripods as to admit of a lateral, sliding motion, but this arrange- 
ment was found to be of no practical advantage, and they were afterwards rigidly attached to the 
tripods. 

After the completion of the tracing of the meridian section of the boundary a reconnoitering 
telescope, with heliotrope attachment (but without any means for imparting slow motion to the 
mirrors), was obtained, and proved to be a valuable addition to these instruments. 

The heliotropes were plainly visible to the naked eye up to .'U) or 40 miles, and on rare occa 
sions up to 85 miles, at which last distance they could generally be seen through tlie telescope of 
the theodolite. 

Not only did the heliotropes ])rove valualde as targets, but they also afforded a ready means 
of communication between the observer and the heliotropers, sometimes by means of the Morse 
code and sometimes by a shorter special code. 

The advantage of being able to communicate freely with an isolated party 20 to 80 miles 
distant, in an unsettled region where supplies are scarce and roads bad, and where, as in one 
case, it took five days' hard travel by pack train to reach it, can scarcely be overestimated, and 
much anxiety is spared when it is known that such a party is well, and properly provided with 
water and provisions. 

In connection with heliotrope communication should be mentioned the experience of Mr. E. L. 
Ingram, assistant engineer, with the 80-mile sight on the California azimuth line between the 
sand dunes west of the Colorado Kiver and the summit of the Coast Bange, where the signals 
were hard to understand and easily mistaken when the light was poor. They failed repeatedly 
until he devised a rough method for imparting slow motion to the mirrors, after which signals 
were received by the front heliotroper, 80 miles distant, with absolute certainty. 

If the heliotrope nurror, as ordinarily mounted, is fastened in its bearings tightly enough to 
resist the action of the wind, it is impossible to impart to it a uniform slow motion, even when 
moved in the most delicate manner by the method generally employed — that of tapping it gently 
with a pencil — and on long sights, where the light is faint and the atmosphere in a state of vibration, 
these iri-egularities of motion are sometimes confused with the flashes of the signal code, and it 



UNITED STATES AND MEXICAN BOUNDARY. 115 

would seem that for extensive use over long- distauces heliotropes provided with telescopic lines 
of sight aud with mirrors capable of a slow and uniform motion would amply repay in efiicieucy. 
their increased first cost. 

To avoid confusion, and in order that the original monuments already alluded to may be more 
readily located on the map, only tlie numbers placed upon them when repaired or rebuilt are given 
in the description which follows. 

PAUALi.Er, M IT . 

The successive steps in tracing the parallels were as follows: 

1. Azimuth oUservations at the iuiti:il point of the tangent. 

2. Tracing tlie tangent. 

3. Observations attlio end of llio tangent to ileterrainc its liack-a/.iiiintli error. 

4. Computing the oflsets. 

5. Lociiting the monnnient sites. 

1. Azimuth ol>.serration>i at the initial point of the tangent. — Tlio instruments and methods 
employed and the results obtained are described in Chapter III, Astronomy, and in the report of 
Mr. J. F. Hayford, assistant astronomer, and need not be repeated here. 

2. Tracing the tangent. — The instruments and targets u.sed in tracing the tangents have already 
been described. The initial direction of the tangent was obtained by turning off an angle of 90^ 
from the meridian through the point of beginning and establishing a point on the tangent at as 
great a distance as practicable. The tangent was then prolonged by the method of reversals, the 
instrument being set up over the last point established and the back-sight being located at the 
most distant previously established point of the tangent visible from the instrument. The tele- 
scope was then transited over and a new point established as far as possible in advance. 

This operation was repeated four times with the telescope alternately direct and reversed, 
and the mean of the four points thus established was accepted as the true prolongation. Bach 
tangent was prolonged until it reached the meridian of the next succeeding astronomical station. 
When a point in advance had thus been established, a heliotrope was set up over it as a foresight 
aud intermediate points were generally " lined in," using range poles as targets, the instrument 
being moved forward from time to time as necessary, as the pole was seldom readily visible more 
than about 3 miles. 

On parallel 31"^ 47' distances along the tangents were measured both by chain and stadia, and 
the stations marking the tangents were located at a distance of 1 kilometer apart. These 
stations were generally marked by a L'-inch by 3-inch stake driven into the ground and projecting 
from 7 to 18 inches above the surface. Around the stake was piled a mouTid of stones to protect 
it from injury. 

A small witness stake was driven out of sight 1 meter south of the station stake, by means 
of which the latter could be replaced in case of removal. 

In establishing points in advance on the tangents by the method of reversals, the two points 
established with the telescope in the same position seldom dift'ered more than a few inches, even 
for distances as great as SO miles, while the other two points established with the telescope in a 
reversed position sometimes differed as much as 10 feet, due largely to the fact that the coUination 
error was very variable owing to the jolting received by the instrument during transportation 
over rough roads. 

Six tangents in all were traced on parallel 31° 47', which are fully described in tlie table in 
section 9, geodesy, of the Report of the Joint Commission. Tangents Nos. 1, 2, 3, and ."i of that 
table are main tangents. The other two are <;heck tangents. 

Owing to the great scarcity of water and the difficulty of getting supplies to the tangent 
party, tai.gent No. 1 was traced at all hours of the day, regardless of atmospheric conditions, and 
on account of the flat character of the country the average length of each prolongation was less 
than 3 miles. As a result of these and other unfavorable conditions the tangent rapidly deviated 
to the north, with a final back-azimuth error at the meridian of Monument No. 15 of 186.fi". 
Refore commencing the erection of monuments this tangent was retraced, for direction only, with 
a probable back-azimuth error of 1". In locating monuments offsets between Monuments Nos. 



IIG 



UNITED STATES AND MEXICAN BOUNDARY. 



3 and -11 were referred to the original tangent and corrected to conforui to the new taugeut. 
Between Monuments Nos. U and l'> ol^sets were referred to tangent No. 13, and the original 
taugeut was uot used. 

3. OhsenHitions at the end of the tdmjent to determine its i>ack-azimuth error. — The azimuth 
observations at the end of the tangent were identical with those at its initial point and served 
both to determine the back-azimuth of this taugeut and to give the initial direction to the new 
one. The ditterence between the observed and theoretical value of the back-azimuth is designated 
as the "back-azimuth error." and indicates the degree of accuracy with which the tangent was 
traced. 

Back-azimuth error of tangenU on parallel Sl^ 47' . 




4. Computing the offsets.— From Appendix 7, Eeport for 1884 of the United States Coast aud 
Geodetic Survey, we have the following general formula for computing difference of latitude: 
-(/ L=K CO.S ;?.B+K3 Sin- Z.C + (dL)- D-7( K^ sin^ Z.E, in which K = distance in meters; L = 
latitude; Z = azimuth of line; R = radius of curvature; N = normal to the polar axis at the 

Station; B= ^, ^ ^ -; G= ^-^^^^-^,, 
R arc 1" 2 R.N arc 1" 

When Z = 90° the above fornmla becomes —d L=K- 0, in wliich —d L is expressed in seconds 
of arc. 

To obtain the offset in meters this must be multiplied l>y the value of 1" of :irc in meters for 
the latitude used. 

For parallel 31° 47', 1" of arc = .".O.SOO meters, and the workin.i;- formula for this parallel 



log d L=2 log K-7..U 402313. 

The offset obtained from this formula is from a theoretically accurately traced tangent to the 
parallel 31° 47' passing through the initial point of the tangent, and may properly be 
designated as the " theoretical offset." 

The identity of the original monuments having been established and their positions located, 
it became neces.sary to compute the offsets from the tangents, as traced, to a curved line joining 
consecutive accepted original monuments, which line should have as nearly as possible the same 
degree of curvature as parallel 31" 47', and would form the actual boundary line to be marked by 
monuments. 

The, offset from the tangent actually traced to the monument curve is composed of four parts: 

(rt) Tiie theoretical offset already described. 

{b) A correction for error in tracing the tangent. 

(c) A constant, measuring the distance of the initial point of the tangent north or south of 
one of the original monuments. 

(d) A proportional part of the distance by which a true geodetic parallel tlirougli one original 
monument passes north or south of the other original monument. 

This may be shown graphically in the following sketch (j). 117), in which tlie offset, K P, to 
the monument curve is a + h+c—d. 

The distribution of the back-azimuth and tangent errors was made in such a manner that 
they would harmonize, inasmuch as one is practically a direct function of the other. In some 
cases the tangent error was measured in the field, and in others it was computed in conformance 
with the distribution of the back-azimuth error. In all cases the known errors received ciarefnl 



UNITED STATES AXD MEXICAN BOUNDARY. 



117 




118 UNITED STATES AND MEXICAN BOUNDARY. 

consideration and were distributed in the simplest possible manner consistent with observed favts. 
(For further details relating to this subject see report of Mr. E. L. Ingram, assistant engineer, 
Appendix 1 of this chapter.) 

Probably the best check upon the method of distribution employed is given in tlie table of 
" Final distances between monuments on parallel 31^ 47','' in section 9 of the Repoit of the Joint 
Commission, where it will be seen that although the United States and Mexican tangents were 
totally different, and traced at different times, the average discrepancy in a nortli and south 
direction between their locations of the -iO new monument sites on this parallel was but 0.435 
meter. 

5. Locating the monument sites. — Tiie field maps and the profiles obtained from the line of 
levels carried along the tangents afforded the means of locating approximately beforehand the 
monument sites at such points that any completed monument would be visible from the two 
adjacent ones. 

Each approximate site was afterwards visited in the field when the monument party arrived 
in the vicinity in order to verify the indications of the field maps and profiles. 

The meridian in which the offset was to be measured was obtained by turning oft' from the 
tangent an angle dependent upon the theoretical azimuth at tlie point plus or minus tlie 
distributed azimuth error at the same point. In this meridian was measured the offset computed 
as already described. Precisely the same operations were executed by the Mexican section of the 
commission from their own tangent and their own measured distances, and the mean of the two 
points thus located was taken as the true location. 

THE MERIDIAN SECTION. 

The methods employed were substantially those used on parallel 31'J 47' except that chaining 
was abandoned; stations were placed at une(iual distances apart and at probable monument sites 
instead of at intervals of 1 kilometer, and the line actually traced was one joining the 3 original 
monuments which marke I the meridian. 

It was found that from a point on the summit of a hill 2 miles south of Monument 40, and 
in the same meridian, Monuments 4() and 4(i and a point on a hill one third of a mile north of 
Monument 53 were visible. 

From this last point, on which was afterwards established a heliotrope as a front sight. Monu- 
ment 53 was also visible. 

Observations showed that the .5 original monuments were in Ihe same straight line, and that 
this line was a true meridian. 

It was intended to locate the intermediate stations on the same line, but owing to the small 
size of the transit used a slight deviatiou occurred between Monuments 40 and 53 amounting to a 
maximum of 1 decimeter. The small offsets from this portion of the line as traced to the true 
meridian were computed and the necessary corrections made before monuments were erected. 



The azimuth observations at the initial point and the metliods employed in tracing the tangent 
were similar to those already described on parallel 31° 47' except that, as in the case of the 
meridian section, the tangent stations were placed at une:|ual intervals on prominent points along 
the tangent. The use of the chain in measuring distances was abandoned at the west end of 
parallel 31° 47' and never afterwards resumed. 

Eight tangents in all, numbered from S to 15 inclusive, were traced on parallel 31'^ 1!0', and 
are fully described in the table in section 9, geodesy, of the Keport of the Joint Commission. 

All of these tangents except Nos. 12 and 15, on which Fauth repeating theodolite No. 725 was 
used, were traced with Wiirdemann repeating theodolite No. 85, which had been used exclusively 
heretofore. 



UNITED STATES AND MEXICAN BOUNDARY. 119 

Jl<irl.-a:imi(lli error uf fangntls on imrallil ,'.7 Jo . 



Tangent. 


Backazim.ith 


Charactnr 
of tangent. 


Tangent. 


Back-azimuth 


Character 
of tangent. 


No. 8 

No. 9 


1 

;i +2:7 
+6.7 

■i 


M.iin. 
Do. 
Do. 
DO. 


No. 12 

No. 13 

No. 14 


12.8 

■Ji. 3 

i 32. 9 

Not measured. 


Main. 

Do. 
Do. 







Gompuiinfi the of sets. — For parallel 3Io 20', 1" of ai'c = .'50.798 meters, aud the working formula 
for computing the theoretical offsets for this parallel becomes : 

log d L = 2 log K — 7.:321C61<1. 

The actual offsets from the tangents as traced to the monument curve were obtained as 
decribed for jiarallel 31° 47'. 

After careful consideration, aided by experience gained on the preceding sections of the 
boundary line, it was decided that no attempt would be made to distribute back-azimuth errors 
of less than ten seconds, but that such errors would be neglected and the tangent assumed to be 
theoretically accurate. 

When the error exceeded ten seconds a careful investigation was made of the conditions 
under which the tangent was traced, and the error was distributed at the points where, in the 
Jndgment of the assistant engineer who traced the tangent, a short back sight, wind, poor light, 
or some similar cause rendered it most probable that the error had occurred. IJy reference to the 
table of back-azimuth errors it will be observed that but 3 tangents on this parallel, Xos. 12. 13, 
and 14, had back-azimuth errors greater than ten seconds. 

The error of tangent 12 was distributed uniformly at each aziinutJi station; that of tangent 
13 at 3 stations where it seemed most probable that errors had occurred, and that of tangent 14 
was distributed throughout its entire length. 

Again applying the only available check upon the accuracy of the treatment of the tangent 
error, i.e., the discrepancy in a north and south direction between the Ignited States and Mexican 
locations of the monument sites, we see that the average discrepancy for the 31 new sites located 
from the 5 tangents on which the back-azimuth error was less than ten seconds, and therefore 
neglected, was 0.454 meter, and that of the 29 sites located from the 3 tangents on which the 
error was distributed was 0.579 meter; the average for the entire 60 new sites being 0.514 meter. 

The monument sites were located in the same manner as were those on parallel 31° 47'. 

THE SONORA AZIMrTH LINE. 

In order that operations might be prosecuted on the Yuma and Colorado deserts in winter, 
the most favorable season for work in the.se localities, the entire i)arty was transferred to Yuma, 
Ariz., in January, 1893, immediately upon the completion of the survey of parallel 31° 20'. 

Two "line parties" were there organized, one under charge of Mr. John F. Hayford, assistant 
astronomer, to trace the boundary line, or the necessary auxiliary lines, from the Colorado Eivcr 
to the west end of parallel 31° 20', and the other under charge of Mr. E. L. Ingram, assistant 
engineer, to operate in a similar manner between the Colorado River and the Pacific Ocean. 

A reconnoissance between Y'uma, Ariz., and Sonoyta, Mexico, made in January and February, 
1893, disclosed the fact that no original monument existed Ijetween Monuments 204 and 175, a 
distance of over 101 miles; that certainly two, and possibly three, excessively rugged mountain 
ranges intervened, and that so precipitous and inaccessible were some portions of these ranges 
that at these points offsets even bnt a few meters in length could be measured only with the 
greatest difficulty. As the two points to be connected were not intervisible, it was of vital 
importance that the auxiliary line traced should approximate as closely as possible to the straight 
line .joining them. It was decided, therefore, to establish a preliminary point on the nearest moun- 
tain range as close as practicable to the line .joining Momunents 204 and 175. This work, which 
proved to be the most difficult and arduous of the entire surve- was successfully accomplished by 



120 UNITED STATES AND MEXICAN BOUNDARY. 

Mr. J. L. Van Ornum, assistant engineer, aided by Messrs. L. S. Smith, trausitmau, and Ernst 
Frank«5, levelman, as follows: 

More extended investigation having shown tliat the line of sight between Monuments 20^1 and 
175 was obstructed by but two mountain ranges, distant about 45 and GO miles, respectively, from 
Monument 204, heliotroi)es were established at each monument and a small transit and a helio- 
trope on each of the intervening ranges. Ou one range a trial point was assumed, and the transit 
ou the other range lined in between it and the adjacent monument heliotrope. This transit was 
then replaced by a heliotrope, and that on the first range was lined in between this heliotrope and 
that at the nearest monument. By numerous repetitions of the same operations successive and 
close approximations to the desired point were obtained, until finally it was located, and a station 
was established on the nearer range (La Sierra de las Tinajas Altas), on what was believed to be 
the straight line joining the two monuments in question. 

When the liue was carefully traced with the Fauth theodolite it was found that this point 
differed but 0.S7 meter from the United States determination of the line joining the monuments, 
and but 0.15 meter from the mean of the United States and Mexican determination of this line. 
It is due to the gentlemen who accomplished this work so successfully to state that o])erations 
were conducted on the dreaded Yuma and Tula deserts; that the two mountain ranges mentioned 
were composed of numerous parallel ridges, rugged and precipitous beyond description, and so 
intersected by huge ravines and deep canons that a change of a few feet in the points established 
by successive approximations frequently necessitated the scaling of a new ridge or peak, an 
operation which sometimes occupied an entire day. 

To add to the diflBculties under which they labored, nearly half of the rodmen deserted on 
this their first experience of the desert, and all of those remaining gave out at the end of two or 
three days, leaving the instrument men to perform their work unassisted. 

A heliotrope was placed as a foresight at the point just described, and the line was traced 
toward it from Monument 204, 73 kilometers distant. This line was produced by three successive 
prolongations, of 25, 4, and 4 kilometers, respectively, to a point on the east ridge of the Tule 
Mountains. This last point was connected with Monument 175 by meaus of a heliotrope placed 
as a target directly over the monument. 

Fauth repeating theodolite No. 725 was used exclusively in line work on the Sonora azimuth 
line, and intermediate points were located at an average distance apart of about 2 kilometers. 
The line was traced in sections by running toward a heliotrope established as far as possible in 
advance. 

Intermediate points were fixed by causing a second heliotroper to establish himself near the 
site of the proposed station, and as closely as possible to the line joining the instrument and 
fixed heliotrope. The angle between the two heliotropes was then measured by the micrometer. 
The observer communicated the result to the intermediate heliotroper by means of the Morse 
code, using a heliotrope kei)t at his station for this purpose. Knowing that each micrometer 
division corresponded to an offset of inm. \>ev kdometer of distance, and estimating his 
distance from the theodolite, the heliotroper readily com])uted the approximate offset to the 
desired line. This he then measured upon the ground and showed his heliotroiie from the new 
position. The observer again measured the angle between the heliotropes and communicated 
the result as before. 

The difference between the first and second micrometer readings, and the known length of 
the measured offset, enabled the heliotroper to determine his previously estimated distance from 
the instrument, and to compute quite accurately a new offset from the point last established. 

This process was repeated until the angle between the two heliotropes measured less than two 
micrometer divisions (2.5"), when the observations were completed by a measurement of this 
angle by 27 pointings, in sets of 3 alternately, with eyepiece micrometer on the two heliotropes. 
Using this measurement and the more accurate stadia distance afterwards determined by the 
topographical party, the small offset from the station as marked to the true line was computed 
and furnished to the monument party previous to the erection of monuments. 

Sometimes as many as seven intermediate points were established from a single instrument 
station; sometimes the instrument was moved up to every new station as established, and occa- 
sionally it was lined in between two fixed points. 



UNITED STATES AND MEXICAN BOUNDARY. 



121 



The time occupied in establishing au iutermediate station within 2.5" of the line, and theu 
measuring the final angle, varied from about thirty to sixty minutes. 

From Monument 175 to Monument 127 each original monument, except Monument 150, was 
visible from the preceding one, and the line was traced by placing a heliotrope over one monument 
and running toward it from the preceding one. 

Monument 150 was not visible from Monument 100, and the peak which intercepted the view, 
Cerro de la Lesna, had sides so nearly vertical and a crest so narrow and disintegrated that it 
was practically impossible to set up an instrument on it in order to " line in " a point on its summit. 
Accordingly, a strong geodetic connection was made around the south side of the peak, by means 
of which points on the line joining the two monuments were established on both its eastern and 
western base, as well as on its summit. (For details of this connection see report of Mr. John F. 
Hayford, assistant astronomer, Ajjpendix i of this chapter.) 

Between Monument 127 and the Colorado River the boundary line as finally marked by 
monuments is a broken line of 12 straight sections, changes of direction occurring at Monuments 
129, 136, 137, 141, 140, 150, 100, 102, 108, 175, and 204. That actually traced by the line party was a 
broken line of 14 straight sections, which at no point, except at Monument 128, differed as much 
as a meter from the line afterwards marked by monuments. 

An old monument which stood 1.81 meters uorth of Monument 128 was connected by the line 
party with Monuments 127 and 129, but this monument was afterwards considered by the engi- 
neers in chief as unauthentic, and the boundary line finally adopted was the straight line joining 
Monuments 127 and 129. 

The inital direction of the line from Monument 204 eastward was obtained from the Yuma 
triaugulation. 

All angles in the broken line traced were measured by micrometer except that at Monument 
175, which was too large for micrometer measurement and was measured by the theodolite used 
as a repeater. In the vicinity of Monument 127 this line was connected with a line of the Nogales 
triaugulation, and the accumulated errors of the azimuth observations at Yuma and JSTogales, the 
triangulatious at these places, and the measurement of 10 angles along the broken line traced was 
found to be but 0.7". 

To show more clearly the departure of the line as marked by monuments from the theoretical 
straight line joining Monuments 127 and 204, the offsets from tlie latter to the accepted original 
monuments were computed by Mr. John F. llayford, assistant astronomer. These offsets are all 
measured to the south and perpendicular to the theoretical line 



Offsets from titeorctival straight line joining Monuments 127 



To Monuments 


Oflset. 


To Monumeut^ 


Offset. 




Meters. 




Meter: 


127 


U U 


150 


657.7 


12S 


li I 


100 


974.9 


136 


J31 1 


102 


1023.8 


137 


1)0 4 


1C8 


1183.6 


Ul 


359 9 


17d 


1413.2 


146 


540 8 


204 


0.0 



The computed angles between the different sections of the Sonora azimuth line, as marked by 
monuments, are given in the following table. The angle is the deviation to north or south of the 
next section from the preceding section i)roduced. 



AtMocu,..e.U- 


Deviation. 


Direction 

of 
deviation. 


At Monuments 


Deviation. 


Direction 

of 
deviation. 




3 28 

13 

1 56 
3 8 


S. 

N. 
S. 
N. 
N. 
S. 


160 


29 

34 

1 46 
55 2 
51 46 


N. 
S. 
S. 
N. 
S. 




162 










146 


204 


i5o::::;;::;::::::::::;. 







S. Doc. 247- 



122 UNITED STATES AND MEXICAN BOUNDARY. 

Ill establishing the uiouumeut sites the very small offsets from the line as traced to that 
which was to be marked had been previonsly computed by the assistant astronomer who traced 
the line, and were measured at right angles to this line. 

The average discrepancy in a uorth-and-south direction between the United States and 
Mexican locations of the 67 new monument sites on the Souora azimuth line was 0.30S meter. 

THE CALIFOKNIA AZIMUTH LINE. 

As uo two of the six original monuments which marked tliis line were iutervisible, it was 
impossible to follow the method employed in tracing the Sonora azimuth lino. 

Accordingly, the line actually traced was a broken line of five straight sections, which at no 
jjoint diverged more than G3 meters from the line finally marked by monuments, itself a broken 
line of five straight sections witli changes of direction at Monuments 220, 221, 252, and the 
monument at Tijuana, destroyed by flood in January, 1895, and replaced by the present JNIonument 
255, situated a little over a kilometer further east. 

The initial direction of the first section traced was a prolongation in two sights, to the 
summit of the Coast Range, of the line joining "Boundary Post" (Monument VII of the original 
survey, which located the junction of the Gila and Colorado rivers) and Monument 207. The 
second section was purposely deviated to the south, and prolonged in a single sight to Mount 
Tecate, with the object of drawing the Hue traced closer to the boundary line and thus reducing the 
length of the offsets, a result which was not attained, owing to the eftects of local deflections of 
theplumbliue. For the purpose of back-azimuth and latitude computations this last section was 
produced to the meridian of Monument 258, passing 140.07 meters south of the monument. The 
third section connected tin; station on Mount Tecate directly with Monument 252; the fourth 
section was traced between Monument 252 aud the monument at Tijuana, afterwards destroyed 
by flood, and the fifth section connected this last monument and Monument 258 on the Pacific. 

Intermediate points were generally established with range poles by running toward a 
heliotrope previously located in advance, the instrument being moved forward as found most 
convenient. 

As the tlieodolite used by Mr. E. L. Ingram, the assistant engineer who traced this line, had 
no micrometer, it was impossible to adopt the method employed on the Sonora azimuth line in 
establishing intermediate points, and was diflftcult to estimate correctly the distance that the 
intermediate targctman should move to come upon the line. Flashes of five seconds' duration 
indicated a movement to the north and of one second a movement to the south, the number of 
flashes giving an approximate idea of the distance. 

Computimj the offsets. — The formulie used in computing the ofisets from the broken line traced 
to that to be marked by monuments are given in the report of Mr. B. L. Ingram, assistant engineer. 
Appendix I of this chapter, and are based on the original stadia measurements, reduced to sea 
level, as the final adjusted latitudes and longitudes, by the use of which were obtained the dis- 
tances in column 7 of the table of "Final distances between monuments on the California azimuth 
line" (section 9, geodesy, of the report of the Joint Commission), and the corrections due to 
remeasurements were not then available. 

From the data then at hand the computed length of the straight line joining Monuments 
207 and 258 was 225,586.2 meters, and the corresponding back-azinuitli error 23.8", Avhich, before 
computing the offsets, was eipially distributed at each of the three main heliotroi)e stations. These 
were located on the sand dunes west of the Colorado Eiver, on the summit of the Coast Range, 
and on Mount Tecate, respectively. This back-azimuth error represents the accumulated errors 
due to the azimuth observations at Yuma and Monument 258, the errors in triangulation at the 
former place, those in tracing the different sections of the broken line, aud in measuring the various 
angles along this line and in the vicinity of Monument 258. 

Later computations based on the final adjusted latitudes and longitudes give the distance 
between Monuments 207 ami 258 as 225,570.2 meters, which would reduce the back-azimuth error 
of 23.8" by but a fractional part of a second. If, as indicated by the close agreement between the 
United States and Mexican stadia measurements of this distance, there is a considerable "station 
error" in longitude between Monuments 207 and 258, and the back-azimuth error be computed, 
using the mean of the United States aud Mexican stadia measurements, it will be found to be 
less than sixteen seconds. 



UNITED STATES AND MEXICAN liOUNDAKY. 



123 



The averaj^e iliscrepaiicy, measured in a north-and-soutli direction, between the United States 
and Mexican locations of the 48 new monument sites on the California azimuth line was 0.467 



■ from the Colorado River toward the Pacific Ocean, the following appreciable computed 
changes of direction occur in the line as finally marked by boundary monuments, the angle given 
in the table being the deviation to north or south of the next section from the preceding section 
produced. 



AtMouuoaen^ 


Deviation. 


Direction 

of 
deviation. 


220 




.. 


S. 


221 




47 


S. 


252 




2 a 


N. 


255 




42 


.. 



In spite of these deviations, however, the most distant monument — No. 220 — from the theoret- 
ical straight line joining Monuments 207 and 258 is situated less than 70 meters north of this line. 

GENERAL KEMAUKS ON TANGENT AND LINE WOUK. 

Mr. John F. Hayfoid, assistant astronomer, personally traced the Souora azimuth line and 
also tangents 12 and 15 of parallel 31'^ 20'. All other tangent and line work was executed person- 
ally by Mr. E. L. Ingram, assistant engineer. 

The successive tangents and straight lines were connected with one another and with the 
astronomical stations, thus forming a geodetic chain from the Rio ftrande to the Pacific, by means 
of which could be computed the station error at the various stations — /. e., the diflference between 
the observed latitude of the station and that transferred, geodetically, from the preceding station, 
a difterence due to local deflections of the plumb line. 

These station errors have been computed and are given in section 13 of the Report of the Joint 
Commission, "Construction of the maps of the boundary." 

All distances measured along the tangents and auxiliary lines, as well as all bases employed 
in triangulation, were reduced to mean sea level of Sau Diego Bay, California, by the formula 

d = *', in which r = the normal corresponding to the base, b, at the level of the .sea: >• + « = that 
»• 

referred to the level of the measured base, B; 3 = the desired correction. 

Owing to the intense heat, so great was the personal discomfort suffered by those engaged in 
work on the desert, aiid so difficult and expensive was it to supply the working parties with pro 
visions, forage, and water, that it was deemed expedient to hasten work with but little regard for 
conditions most favorable for observations, as it was believed that sufficient accuracy could be 
obtained and a great saving in expense eftected. 

As an extreme instance of the difficulties under which work was prosecuted, it may be men- 
tioned that at one point on the Tule Desert all of the water for men and animals was carried 102 
miles — 30 miles in tank cars, from Yuma to Adonde Siding on the Southern Pacific Railway, and 72 
miles in water wagons, from that point to the camp on the desert. 

As much of the observing, both on the Sonora and California azimuth lines, was done under 
conditions api^arently so unfavorable, it may be interesting to give, in addition to the back-azimuth 
errors and discrepancies between United States and Mexican locations of monument sites already 
mentioned, the results of experiments made by Mr. John F. Hayford, assistant astronomer, on the 
Sonora azinmth line, as to the accuiacy of pointings upon the heliotropes and the remarkable 
variations in the apparent size of their lights, which variation was fully confirmed in every respect 
by observations made by Mr. E. L. Ingram, assistant engineer, on the California azimuth line. 

From May S to September 15, 1.893, a record was kept during observations, of the temperature, 
the appearance of the heliotropes, and the apparent diameter of the heliotrope light as measured 
by the micrometer. 

The shade temperatures during observatious varied from 77° F. to 118'^ F., averaging about 
100- F. 



124 



UNITED STATES AND MEXICAN BOUNDARY. 



The apparent diameter of tbe heliotrope light iu divisions of the micrometer, 1.24" each, 
varied from 5 to 104 divisions; the first occurring in the morning or on a cloudy day, and the last, 
in a single case, a little before noon of a very hot July day on a sight of 2 kilometers, passing 
within 3 meters of almost bare sand. The average apparent diaineter of the light from all 
measurements was 25 divisions =31". The diameter of the principal mirror of one hcliotroi)e was 
10 centimeters, that of the other was 7.5 centimeters. 

Computations based upon the distance to the heliotrope light and its apparent diameter, as 
measured by the micrometer, showed that the mirror itself was visible upon very rare occasions, 
if ever, but that the apparent diameter of the light was many times that of the heliotrope mirror; 
for example, iu one instance the measured apparent diameter of the light of the 10-centimeter 
mirror corresponded to that of a target ll.t meters in diameter placed where the heliotrope was 
located, 43 kilometers distant. 

Although varying greatly at different times, it may be stated in general terms that the meas- 
ui'ed angle, subtended by the apparent diameter of the light, was independent of its distance 
from the instrument; for example, at 2,000 meters a mean of 3 different measurements gave the 
apparent diameter of the light of the 10-centimeter mirror as 19 micrometer divisions, while at a 
mean distance of 40,500 meters the mean of 37 different measurements M-as 20 divisions. Not 
only were there abnormal variations in the apparent size of the light, but also in its form. When 
a steady breeze was blowing across the line of sight the disk of light appeared flattened on the 
windward side and blown out on the leeward side, very much as would be the flame of a candle. 
When great distortion of the size of the light occurred it frequently appeared blurred, and always 
with one part of the blur brighter than the rest. Generally the bright region was iu the center, 
but sometimes it was unsymmetrically situated with reference to the outline of the light. "In 
those cases the brightest region was always to windward of the center of the blur and the leeward 
part of the outline vibrated more violently than the windward side." (For further details of these 
investigations see report of Mr. John F. Hayford, assistant astronomer, Api)endix 4 of this 
chapter.) 

In all cases pointings were made in sets of 3, upon the center of the brightest part of the 
light. 

In spite of the apparent distortion of the light as regards size and form, tlie accuracy of the 
pointings was not greatly affected thereby, as is shown by the following table, in wliich zAs is 
the mean of the ditt'erences between each of the 3 ijointings of the set and the mean of the 3. 



Heliotrope 


with ]0e 


utimeter 


Heliotrope with 7.5centimeter 


Diameter, 
divisions. 


., 


Number 
of obacr- 
vations. 


Diameter, 
divisions. 


A3 


Number 
ofohser- 


U-15 
10-28 
29-67 


U.82 
1.05 
1.43 


42 
46 
38- 


1 0-20 

I 21-34 

35-104 


0.78 
0.88 
1.61 


77 
71 
48 



The maximum value of ^3 in the above table corresponds to ±2.7" for the probable error of 
a single pointing, and justifies, so far as accidental errors are concerned, observations made under 
such apparently unfavorable conditions. 

Observations made iu the Tule Mountains to determine whether there was any apparent dis- 
placement of the light when the heliotrope was neglected, and whether the apparent position of 
the light coincided with the actual position of the heliotrope mirror, showed that at 4 kilometers 
distant the heliotrope light seemed to be 0.19" south of a pole with which it had been accurately 
ranged iu line, but did not prove "'conclusively that there was any apparent change in the position 
of the light when the mirrors were neglected" from fifteen to twenty-five minutes at a time. 

"The accidental errors of pointing seemed to be slightly greater when the mirrors were first 
adjusted than later when the light had become less bright and apparently smaller." 

Observations made at a distance of 5,S00 meters to ascertain the effect of reducing the 7.5- 
centimeter mirror to a diameter of 2.5 centimeters showed that the apparent diameter of the full- 
sized light was 25 divisions, while that of the reduced light was 23 divisions, and that the latter 
appeared almost as bright as the former. "The accidental errors were as great with the reduced 
as with the full light." 



UNITED STATES AND MEXICAN BOUNDARY. 



125 



At Momimeut l(>s special investigation was made "to (leterinlni' wlietlier tbere was a 
systematic ditt'erence between forenoon and afternoon oliseivations, and wlietlier there was any 
systematic error due to tlie position of the back glass," 

The resnlt showed tiiat the heliotrope a[)peared to be 0.74" fartiier south in the forenoon than 
in the afternoon, and that the i)osition of the back glass north or sonth of the line did not aflect 
the result. 

To detect constant or systematic errors a line 25,.S00 meters in length was located, both by 
lining in points ahead and by lining in the instrument between two known points. 

"The greatest difference between the two locations at any of the 10 intermediate stations was 
32 centimeters and the average difference 17 centimeters. With one exception, all stations as 
located by the second method were tarther south than by the first method." 

A few experiments made by Mr. E. L. Ingram, assistant engineer, seemed to indicate that an 
eastandwest line traced toward the west, with heliotropes a.^ targets, had a tendency to turn 
toward the north, a statement which is partially confirmed by the fact that 9 out of 11 lines 
checked had positive backajciinuth errors, and consequently deviated toward the north. 

Another peculiar phase of heliotrope action was often observed, i. e., the much greater actual 
dispersion of the exterior rays of the eoiie of retlected rays than should have been the case 
theoretically. 

In conclusion it may be stated that all experiments and invesligations confirmed in the most 
satisfactory manner the reliability of heliotropes as targets under the apparently unfavorable 
conditions under which they were employed on this survey. 

TI5IANGULATION IN VICINITY OF EL PASO. 

A base was measured on the railroad near Astronomical Station No. 1 and a triangulation 
laid out from this base connecting Astronomical Station No. 1 with Monuments 1, 2, and 3, and 
the magnetic station near No. 1, and with the United States longitude station at El Paso; also 
with the public buildings in El Paso and Juarez. 

The following is a list of the geographical positions of the objects determined, and a sketch 
of the triangulation is given at the end of this chapter. 



(!eoi)raphicul positions of poitits in the 



ity of Kl Paso, Tex. 



Stations. Latitude. LongituJi-. Azimuth. 


B.-ick azimuth. 


To stations. Distance. 


A.stronomical, No. 1 


31 46 .59.40 
31 47 15.53 

31 46 57.68 


106 31 25.07 
106 31 24.81 

106 31 23.98 
100 31 39 03 


!I0 00 16.4 
180 58 23.2 
178 30 40.1 
36 58 21.1 
357 44 20.5 
05 24 48.6 
W 29 24.1 
86 13 20.5 
313 49 15.4 
97 37 00.9 
92 44 18.0 
91 09 23.1 
102 23 14.2 


270 00 09.1 
58 23.4 


Monument Xo. 1 


..... 
305.4 


Azimuthmarli 

Monument No. 1 

South base 


1,805.8 
621.7 
550 035 


216 58 13.6 
177 44 20.9 
245 24 26.9 
244 29 02.0 
266 12 42.3 
133 49 40.0 
277 36 5:1.0 
272 43 55.9 
271 09 00.6 
282 22 35.6 


South base 


Monument No. 2 


1,193.6 






Monument Xo.l 

MoDumentNo.2 

A * 

IJ 


1, 707. 
399.1 
1, 108. 4 
1,126.1 
1, 975. 




Monimient No 1 


31 46 59 40 






















203 50 38.6 
270 23 45 2 


83 51 47.5 
nn 9.5 in i 




3,460.4 
4,243.8 
2, 425. 9 
5, 766. 1 
5,403.5 
6,929.1 


1 • 


A 


A 


31 46. 58.42 

I ;; - 

31 45 29.79 
31 45 27.64 
31 44 15.90 


106 .■12 06.78 
106 32 37 31 


285 39 37.1 105 40 23.8 
298 59 29.1 119 01 10.0 
300 19 53.4 120 21 26.7 
316 14 26.2 136 16 02.0 

1 


c 


B 


Courthouse 

Feileral building 

CathedralJuarez 










3,451.2 
3,117.7 
4,995.4 


Federal building 


106 29 9.57 
106 23 55.13 
106 29 4.73 


311 42 46.5 ; 131 43, 33.1 
330 33-25.7 150 34 14.8 


Federal building 

Cathedral Juarez 








Cathedral Juarez 


: 






1 





126 



UMTED STATES AND MEXICAN BOUNDARY. 



TRIANdULATION AT SAN PKDRO RIVER. 

A iiioimmeut of dressed stone was found on the east bank of the San Pedro Eiver, and the 
astronomical observations of the United States section were made near the nionumeut, at Astro- 
nomical Station No. 10. 

Afterwards ajiother monumeMt, consisting only of a pile of loose stones, was found on the west 
bank of the river and was recognized as the one erected by Emory. It was evident that tiie 
monument found on the east bank of the river was the one erected by Salazar, who did not find 
the one erected by Emory on the west bank. By an agreement of the joint commission (see pp. 37 
and 38, Emory's report), the one erected by Emory on the west bank was to be recognized as the 
one marking the boundary. 

A triangulatiou connecting these monuments was made by the United States section by means 
of a measured base line and a (juadrilateial cofluecting Astronomical Station No. 10, near Salazar's 
monument, with Station A on tangent line near Emory's monument. 

The difference of latitude between these stations was found to he -f 30.08", and between Sala- 
zar's monument and that of I'hnory + 20.07", the latitude of Sal;i/,ar's nionniiient being 31^ 19' 35" 
and Monument 20 of Emory being 31° 20' 4.67". 

As the observations of the Mexican section were made directly at the monument of Emory, 
theii' result for its latitude (No. 08, new) of 31° 20' 3.02" ± 175" was accepted in 1895 as tlie true 
latitude of Monument 98; the difference in station error in latitude accounting for the difference 
of the two results, = 1.65". 

TRIANGULATION AT NOGALES. 



A base line, 724.96 meters long, was carefully measured on the railroad at Nogales, Mexico, 
and a triangulatiou made connecting the United States survey huigitude .station at Nogales, Ariz., 
with the azimuth station. Monument 122, and various buildings in Nogales on both sides of the 
boundary line. 

This station was also occupieil by both United States and Mexican sections tor latitude 
observations. 

This triangulatiou transfers the latitude and longitude of the astronomical station at Nogales, 
Ariz., to Monument 127 at the intersection of the parallel of 31o 20' with the one hundred and 
eleventh meridian of longitude, as determined by Emory. 

Points on the tangent through the azinuith station at Nogales, Ariz., were also determined, 
giving the lengths of portions of tlie tangent independent of the stadia measurements. 

A sketch of the triangulatiou will be found at the end of this chapter, and a list of geographical 
positions follows: 



raphical jiositions of points 



ill/ nf Xogales, .Iriz. 



Azimuth. , Back-azimuth. 



Astronomical static 
Azimuth station... 

No.l 

N0.4 

N0.2 

N0.3 

South base 

North base 



31 20 U4. 

31 20 00. 

31 19 .'il. 

31 18 .'•.9. 



82 110 f>5 



31 



26.55 110 



31 19 27.41 



31 19 50.79 



24.77 
.17.14 
34.07 
01.45 
41.24 I 
47.81 



147 13 47.2 



126 03 
289 36 
188 21 



86 15 
85 47 
161 46 



327 13 45.5 



306 02 34.2 



246 50 20.7 
266 14 47.7 



341 45 50. 7 



210 52 43. ( 



No.l.. 
N0.2.. 
No. 1 . . 
Sonth 
No. 2.. 



UNITED STATES AND MEXICAN BOUNDARY. 
Geographical positions of points in vacinily of Noijalea, Ari:. — C'oi 



127 



Xo.5 

No.6 

No.7 

No.8 

B 

Monument XIX* 

Comer Monument 127 

Levys store (flag poJe) 

Montezuma Hotel («:!•; pole) - 



Mexican 



, (Hag 



Flag C. 
FlagD 
FlagE. 
FlagF. 
FUgG. 
FlagH 
Flag I. 
FlagK 
FlagM 



:il 20 11.52 



31 21 40. 55 



31 la .■.;.. 2C j 

31 20 00.33 

31 20 00. 33 

31 20 00.32 

31 20 00.31 

31 20 00.30 

31 20 00.29 

31 20 00.26 

31 20 00.22 



274 43 15. 2 

290 19 08.0 

183 52 54.3 

247 18 36.3 

286 09 23.9 

301 41 11.5 

163 40 16.6 \ 

283 30 08.8 

165 .54 15.8 

335 31 47.4 

110 07 10.9 

160 U 24.1 

272 43 41.5 

65 07 07.' 

63 35 21.3 

285 34 

313 47 19.9 



94 45 08. 6 j No. 3. , 

110 21 05.1 ! No. 4. 

3 52 58.3 ! No. 5. 

67 20 33.7 No. 3. 

106 12 29.9 

121 44 13.4 



110 56 43.15 


58 22 06.6 
73 37 24.6 
233 54 47.8 


110 57 10.03 




















111 00 30 69 








111 04 26 00 









No. 5 
No. 6. 



345 54 01.1 No.7. 
155 31 54. 3 



310 14 9K] 



245 06 55.7 



105 34 35.7 



3,911.8 

8,381.6 

3, 075. 5 

847.1 



B 395.7 

No.7 1 3,314.2 

Azimuth station 258. 3 

No.l [ 058.9 

....do ' 725.0 

Azimuth station 214.3 



Astronomical- 



3, 526. U 
4,470.4 
5, 228. 
6, 501. 2 
8, 289. 2 
12, 722. 2 



TKIANCTTLATION IN VICINITY f)F YUMA, ARIZ. 

A base 2,203 meters long was measured on the level mesa east of the town of Yuma, aud an 
extensive system of triaiigulation made connecting the astronomical station in the corral of the 
TJnited States Quartermaster's Department, occupied by the Coast and Geodetic Survey for longi- 
tude, and by both the United States and Mexican sections for latitude, with the azimuth station 
of the United States section, with Monuments No. 207, on the west side of the Colorado River, 
and No. 205, on the east side of the same river 20 miles below the junction of the Gila aud Colo- 
rado. It was necessary to elevate the theodolite at Monument 205 about 25 feet by means of a 
tripod and scaffold to see the azimuth station. 

Station No. XXXVII of Tangent A, on the west ridge of the Tiimjas Mountains, was deter- 
mined, thus measuring by triaiigulation the distance of this station from Monument 204, giving a 
valuable check on the same distance as measured by stadia. 



128 



UNITED STATES AND MEXICAN BOUNDARY. 
Geogra2>hical poailioii) of points in vicinit>) of Yuma, Ariz. 



Latitude station 

Azimuth station 

Eaat base 

Nn.9 

No. 10 

Pilot Kiiol> 

No. II 

Monument 204 

Station XXXVII, line A, on 

Tinaja.'i Mts. 
B 

Uountlary post 

Indian scliool (Hag jiole) 

Penitentiary (jiolu 1) 

P.-nilentiary (pole 2) ' 

FlagE 

Monnment 207 

FlagF .'.. 

rlagG 



53.83 
23.38 ' 



34.82 
3.'-.. 40 
01. 33 
01. 8C 



114 30 

114 37 

114 38 

114 35 

114 44 

114 49 

114 46 

114 02 

114 37 

114 36 

114 37 

114 36 

114 36 

114 44 



178 32 01.12 



224 24 37.4 
182 34 51.2 
207 09 59.1 



54. 91 265 

59 

48. 45 265 



238 59 32.5 



36 15.6 

55 52.2 

45 05.8 
49 32.5 
5B 35.2 
22 39.2 
41 55.1 
05 02.4 

46 00.9 
36 38.9 
46 00.8 
39 42.8 
39 55.7 
29 10. 
29 14.3 
21 36.8 
28 28.8 
27 36.7 
09 58.8 
25 30.5 
13 27.3 



332 63 22.2 



2 34 55.8 
27 10 49.0 I 
271 18 46,6 



273 45 26. 

169 58 4G.9 

190 22 33.3 

181 41 53.7 

270 00 51.1 

189 4r, 54.8 

247 36 28.9 

189 45 54. G 

272 35 26.7 

322 39 30. 1 

85 32 50.3 

265 29 10.0 

28 21 5G.9 

85 32 51.7 

85 32 50.3 



Latitude station . 
Azimuth mark-.. 
Azimuth station . 



Azimuth station . 



No.ll 

No. 10 

No.lO 

Monument 204... 
Azimuth .station. 

Pilot Knob 

East base 

Azimuth station. 



Pilot Knob 

Azimuth station. 



Azinuitli station. 
Pilot Knob 



1, 858. 
1, 910. 9 
4, 987. 3 
5,275.6 
4, 166. 4 
6, 949. 
12, 253. 
13,578.9 
9, 002. 
22, 739. 2 
23, 330. 5 
25, 844. 4 
06, 963. 
73, 095. 5 
1,515.0 
11,871.3 
3, 243. 7 
1, 565. 9 
2, 279. 2 
12, 103. 5 
1,728.0 
523. 8 
1,748.0 
12, 345. 8 



2,035.2 
12, 852. G 
15,154.4 

5, 190. 
21,255.9 

2, 717. 3 



Appendix No. 1. 

Report of Mr. E. L. Ingram, Assintant Engineer. 

San Diego, Cal., Ocfohrr 37, 1S9J. 
Followiug are the final reports oii tangent and line work intrusted to my care during the 
progress of the iireseut survey : 

1. Report of tangent work, par.allel 31 47' N. 

2. Report of line work, meridian line. 

;{. Report of tangent work, parallel 31^^ 20' N. 

•1. Report of line work, azimutli line, Colorailo River to Pacil'io. 

5. General report, common to all lines. 

1. Report of tam/ent work, parallel 31° 47' J\'.— Work in my charge: Parallel ^iio 47' ^as 
located by the taugent (to the prime vertical) and offset method. Tlie duty assigned to me was to 
locate and mark in the Held such tangents as were necessary for this pui'ijose; to measure these 
tangents by chaining; to locate existing monuments with reference to tangents, and to make such 
other measurements and computations as were necessary and appropriate to the work in hand. 

Size of camp : The camp was made up of my own party proiter, together with several members 
of the topographical party, and the necessary help. The number of men varied more or less, but 



UNITED STATES AND MEXICAN BOUNDARY. 129 

was about as follows: Tangent party — myself in charge — 1 recorder, 2 cliaiiunen, 4 targetmen; 
level party— 1 levelnian, 2 rodinen; stadia party—l transitniaii, 2 nxlnieu; help— 1 cook, 3 
teamsters. 

Transportation: This was also very variable, but was about as follows: One baggage wagon 
with 4 mules, 1 water-tank wagon with (J mules, 1 spring wagon with 2 mules, 1 pack mule, 
1 saddle horse. 

Supplies: These were furnished by the (piarterniaster, usually without the help of the camp 
transportation. 

Stations: Line stations were driven at each whole kilometer along each tangent, counting 
from its initial point, in addition to the main stations at the ends of the successive i)rolongatious. 

Eerunning of tangent No. 1: According to instructions, tangent No. 1 wa.s run at all hours of 
the day over a bui-ning mesa, regardless of all atmospheric conditions, in order to make ((uick 
time over a bad stretch of desert. In addition to this the average length of each prolongation 
was less than 3 miles, owing to the rolling nature of the country traversed. As a consequence of 
these and other unfavorable conditions tangent No. 1 deviated rai)idly to the north, with a final 
azimuth error of 180.0" at the meridian of Astronomical Station No. 2. Before commencing 
monument work I reran this tangent, for direction only, with a probable backazinuith error of 1", 
as well as it could be determined. In the actual location of momiments everything was referred 
to the original tangent, based on corrections derived from the new tangent. Between new Monu- 
ments Nos. 11 and 15 tangent No. 2 was used iu place of No. 1. 

Check tangents: Tangents Nos. 1,2, 3, and 5 are the main tangents. New No. 1 and No. 3a 
and No. 4 are check tangents, exerting their influence in the final location of the monument curve. 

Dates: The work iu my charge commenced February 12, 1892, and ended April 23, 1892. 

2. Report of meridian line. — Work iu my charge: Practically the same, except that a meridian 
line through the existing monuments was located in place of a series of tangents; chaining was 
abandoned, and stations were placed at probable monument sites iu place of kilometer points; 
slightly reducing the size of the ])arty, the size of camp and amount of transportation remaining 
about as before. 

Dates: Meridian work was commenced April 29, 1892, and ended May 23, 1892. 

Method of running line: This line was run practically as a single sight. A hill 2 miles south 
of and seeing Monument 40 and a hill one third of a mile north of and seeing Monument 53 were 
found to be intervisible, and Monument 40 was found to be visible from the northern hill. Obser- 
vations at the dilfereut points of view proved the three monuments to be truly in line with each 
other and on a true meridian. It was iutended that the intermediate points located should also 
be on this line, but owing to the small transit used a deviation (1 decimeter) occurred in the lower 
part of the line and had to be* corrected by offsets when the new mouuments were located. At 
the upper corner a true meridian was established by the astronomical party, and the monument 
line was found to coincide therewith. At the lower corner it became necessary to use the Wiirde- 
mann theodolite to connect with tlie azimuth station, making the result unreliable to at least 5". 
The actual result obtained, if correct, would indicate a deviation of 3.4" to the east in running 
northward. 

3. Rei)ort of tangent irorl;, parallel 31^ 20' K. — Work iu my charge: The duties assigned to 
me on this parallel remained practically the .same as before, with the addition of a small amount 
of topography iu the vicinity of Nogales, Ariz. During my absence on monument work (August 
15-November 5, 1892) one tangent (No. 12) was run entirely by J. F. Hayford, assistant astron 
omer. Mr. Hayford also ran tangent No. 15 while I was engaged on topographical work. 

Camp and transportation : The size of the camp and amount of transportation was extremely 
variable, and were further modified by the topographical party, which was sometimes with ray 
camp and sometimes detached. 

Supplies: These continued to come through the quartermaster, depending partially on the 
camp transportation for their delivery. 

Dates: Tangent work, May 2G, 1892, to August 15, 1892, November 5, 1892, to December 0, 
1892; absent on monument work, August 15, 1892, to November 5, 1892; engaged on topograpical 
work, December 7, 1892, to Jauuary 9, 189.3. 



130 TINITl'.n STATES AND MEXICAN BOUNDARY. 

4. Reporto/liiie irorh; OH azimuth line, Colorado Biver to Pacific, — Work iu my charge: All 
the work of this part of the survey, iucliuling liue, level, and topographical work. This, of course, 
does not iuclude the astronomical observatious for azimuth, made at each end of the line by J. F. 
Hayford, assistant astronomer, nor the triangulation from Yuma to Monument 207, which was also 
iu charge of Mr. Hayford. 

Size of camp: The camp varied in size with the character of the country traversed, but for 
the greater part of the time was about as follows: Myself, in charge, 2 transitnien, 1 levelman, 10 
rodmen, 2 packers, 1 guide, 4 teamsters, 1 cook, 1 cook's helper. 

Transportation : Variable, but about as follows for the bulk of the time : Two baggage wagons 
with 4 mules each, 1 water-tank wagon with 6 mules, 1 spring wagon with 2 mules, pack mules, 
2 saddle horses. 

Supplies: Up to May 10, 1893, all supplies were obtained from the quartermaster. From this 
date to September 20, 1893 (breaking up of camp), all supplies were purchased directly by myself 
as needed from time to time, and hauled by the camp transportation. 

Level and topographical work: The methods established by J. L. Van Ornum, assistant 
engineer, were adhered to in this part of the work. 

Line work : A broken line was run from the " Boundary post" in Yuma to the initial monument 
on the Pacific Coast. The line as actually marked in tlie Held is best seen from the sketch given 
in the monument report, but may be described as follows: 

Boundary post to Station 3 I (Coast Range) = prolongation of direction of liue from boundary 
post to Monument 207. 

Station 3 I — 1 L (Mount Tecate) deviates S' 52" to south from previous line. 

Station 4 L — Monument 252 runs direct between these points. 

Monument 252 — old Monument II runs direct between these points. 

Old Monument II — Monument 258 runs direct between these points. 

Deviation at Station 4 L = 16' 12,3" north. 

Deviation at Monument 252 — 8' 22.9" south. 

Deviation at old Monument II = 0' 38.2" north. 

The angles here given are computed values, and subject to coirection for errors in distances 
and back-azimuth error. 

The direction Station 3 I — i L was also prolonged to the meridian of Monument 258 (passing 
140.07 meters south) for the purpose of back-azimuth and latitude work, and furnished the basis 
for computing the angles above given, which could not be directly measured as easily with equal 
accuracy. 

Tlie object of the "deviation at Station 3 I was to draw the located line closer to the actual 
monument line, but owing to the large station error between boundary post and Monument 258 
this result was not achieved. 

The main heliotrope stations, or points from which the successive prolongations were made, 
are Station K, Station 3 I, and Station 4 L, and an equal distribution of back-azimuth error 
( + 23.8") at these points is probably the best that can be done. 

Dates: Line work commenced January 14, 1893, and ended September 20, 1893, when the camp 
was disbanded and I was ordered to San Diego for office work. 

5. General report. — The following notes and remarks, applying to all the tangent and line work, 
are here grouped together to avoid unnecessary repetition. 

All measurements are metric. All lines and tangents were run with Wiirdemaun theodolite 
No. 85, which is an Sinch repeater of the pillar pattern. In considering the results obtained it is 
but fair to remember that this instrument is extremely old, both in design and service, and capable 
of any use at all only with the greatest care. Fortunately it was possessed of a telescope of most 
unusual excellence. 

In the early part of the work the lines were extended by sighting on wooden targets about 3 
feet square, mounted with a sliding motion on wooden tripods. These targets were painted black 
and white, and various designs were experimented with without success, and fiually the targets 
were given up entirely iu favor of heliotropes. As far as visible (about 3 miles) a common range 
pole was capable of far more accurate alignment than any of the targets. Beyond 3 miles, in spite 
of their size, the targets were as hard to distinguish as a range pole. A similar experience occurred 



UNITED STATES AND MEXICAN ROUNDARY. 131 

later in the work in a slightly <lit1ereiit iiiaiiner, and is considered of siinicient interest to be inserted 
here. 

Observations for azininth were taken at Monument 220, near New Kiver, and the following 
morning the angle between the line and the azimuth box was sought to be measured. The azimuth 
box was less than 2 miles from the instrument, and the front of the box was divided into three 
equal stripes, the central one being white and the others black. Each stripe was G inches wide 
and 12 inches high. On top of the box was a white stick 1 inch in diameter and 12 inches high. 
Contrary to all expectations, the box api)eared merely as a dim haze, even with the sun shining 
directly on it, and was entirely useless for sighting at with the intention of measuring an angle 
with any accuracy. The little stick, however, stood out with startling clearness and was bisected 
with ease and certainty. 

The heliotropes which were used after the wooden targets were abandoned were simple little 
affairs without adjustments of any kind; were provided with mirrors 3 inches in diameter; at 
first mounted with a sliding motion, but finally attached rigidly to light wooden tripods. These 
little heliotropes were easily visible 30 miles to the naked eye, and could be seen 80 miles with the 
theodolite. The appearance of the heliotroi)e light varied greatly under dittereut conditions. At 
sunrise and sunset the cross hair of the telescope was sufficient to obscture the whole light. Within 
an hour or less of those times the light appeared about three to five times the apparent width of the 
cross hair.. In the iniddle of the day the light grew to enormous proiwrtions, covering as much 
as five minutes of arc. The angular width of the light remained about the same, regardless of 
distance. The light usually became more and more unsteatly as it increased in size, in the middle 
of the day appearing to be in an intense state of vibration in all directions, and changing its size 
and shape with remarkable rapidity. In the middle of the day the light lost its dazzling appear- 
ance almost entirely and was frequently hard to distinguish from a white flag, even to the trained 
eye. This effect was also noticed when the light was not accurately pointed at the observer. 
When a strong wind was blowing the light apparently elongated in the direction of the wind, 
assuming an oval form, with the pointed part going with the wind. The pointed part then waved 
and fluttered just like the edge of a flag in a gale. It may here be observed that all these effects 
appeared in less degree in proportion as the light was more truly pointed at the observer (as 
judged by the brightness of the light), and it is the opinion of the writer that a heliotrope with 
teloscopic line of siglit and slow-motion mirrors would be worth many, many times the extra cost 
of manufacture. In this connection it may be mentioned that signals are hard to understand, and 
easily mistaken when the light is poor, as found on the SO-mile shot west of the Colorado Eiver, 
where the signals failed rei)eatedly until the mirrors were provided with a rough attemjrt at 
slow motion by wooden levers about a foot long, held in place by light friction. With this new 
arrangement the signals were received at the SO-mile point with absolute certainty, and obeyed 
immediately and correctly. 

If the mirror as ordinarily mounted is screwed so tight in its bearings as to safely resist the 
whirling effect of the wind it will move by fits and starts, even if moved in the most delicate way, 
which is by jarring it around with the tapping of a pencil. It is further believed that when the 
light is not truly pointed the visible image is not concentric with the center of the mirror, which 
is a very serious matter if true. If the light is directed incorrectly in a vertical direction there is 
little or no reason to expect that it makes any particular difference, except in the way of annoyance; 
but if it is swung slightly to one side or the other it seems not unreasonable that it may twist 
the line of sight. Unfortunately this point has never been determined without doubt, and my 
theodolite, having no micrometer eyepiece, was not well adapted to such a determination. A few 
experiments were made, however, when opportunity offered, and seemed to indicate that an east 
and west line had a tendency to turn northward from this cause. It will be noticed also from the 
line reports that nine out of eleven lines have a positive back-azimuth error, indicating that the 
successive prolongations have deviated northward. 

After the completion of the meridian line a reconnoitering telescope, with heliotrope 
attachments (without slow motion), was added to the outfit and proved very valuable on account 
of its telescopic line of sight. 

All level work in my charge was done with a Gurley wye level of the usual pattern, using 
the methods established by Mr. J. L. Van Ornum, assistant engineer. 



132 UNITED STATES AND MEXICAN liOUNDARY. 

All topograpliifal work in my charge was done wiMi a Giuch Braudis eugineer's transit, using 
tlie methods established by J. L. ^^an Orniim, assistant engineer. 

The small instruments composing the balance of the outfit were such as are ordinarily used, 
the tajjes, chains, level rods, etc., all being metric. 

The stations marking the line differed somewhat at ditterent times, but in general consisted 
of 2-iuch by 3 iucli stakes projecting from (5 to 18 inches above the ground and surrounded with 
stones for protection. A tiag was usu.ally left accurately on liue near each station, for the benefit 
of the following jjarties. A small stake, usually 1 by 1 by inches, was driven. out of sight 
approximately south of each statioii at a distance of 1 meter, to be used as a witness if the main 
stake suffered any dei-angement. On the meridian line the witness stakes were put to the west. 
In point of fact, the main stakes were scarely ever found disturbed, even after twelve or more 
months from time of placing. In the sand dunes, of course, a number of stakes disappeared, but 
in this case the witnesses were also gone. 

The work on different parts of the boundary difVered very much in theory, but the actnal 
field work was practically the same in all cases, and consisted in establishing as nearly as possible 
a long, straight line over a given stretch of country by successive prolongations of a given initial 
direction. On parallels 31° 47' and 31° 20' the lines run were tangents to the prime vertical at or 
near the corresponding astronomical stations, the initial directions being jointly established by 
J. F. Hayford, assistant astronomer, and myself. The meridian line was run practically in a 
single sight. The azimuth lino (Colorado River to Pacific) was run part way with the initiiil 
direction Boundary Post and Monument 207, and afterwards changed in direction, as explained in 
the detailed report thereon. 

The object in every case was to obtain a straight line conveniently near existing monuments, 
and of such a nature that the actual boundary could readily be located by a series of easily 
computed offsets. The formula' an<l constants pertaining to the work being more intimately 
related to the discussion of monument locatiou are all given in the monument renort and not 
repeated here. 

The various straight lines were prolonged by myself personally, using the method of reversals. 
The instrument was set up over the last point established in any case, aud carefully leveled with 
the striding level while pointing at the furthest visible point previously established. The telescope 
was then transited over and a new point lined in ahead as far as could be seen. This operation 
was repeated four times, the telescope being alternately direct aud reversed to eliminate level and 
collimation errors, aud the mean of the four new points thus located was considered to be the 
correct prolongation sought. Sometimes more or less than four points were used under peculiar 
conditions, but the general rule was the mean of four points. Each line was thus prolonged until it 
reached the meridian of the next succeeding astronomical station, where its back azimuth was 
determined and compared with the theoretical value. All the astronomical stations were located 
with reference to both the old and new tangents, so that the series of tangents formed a continuous 
chain throughout the work. 

The theodolite used had no micrometer eyepiece, and hence the distance necessary for the 
forward heliotrope man to move to come into line could ouly be roughly estimated. The signals 
used were therefore of the simplest character. Long flashes (five secouds) of the heliotrope 
directed a movement to the north, and short flashes (one second) a movement to tlie south, the 
number of flashes giving a rude idea how far to move. When the forward heliotrope went out it 
meant it was being moved in response to the signal. When the light was judged to be on line a 
long, steady light (about thirty seconds) was shown, and responded to by three long flashes when 
understood, and the i)oint thus established was marked on the ground. When the requisite 
number of points was located, and the mean established, the forward man kept a steady light 
while intermediate points were established at convenient places. A code of simple signals was 
also established for commencing and finishing work each day, going to lunch, etc., such as would 
naturally suggest themselves. Intermediate points were usually set with range poles, the 
instrument being moved forward from time to time as convenient. 

It would hardly occur to anyone that there could be any difference between having the 
vertical hair of the telescope central with the heliotrope light and having the light central with 
the hair; but such proved to be the case. If the eye gives its chief attention to the light the hair 



UNITKD STATES AND MEXICAN BOUNDARY. 



133 



soon becomes unsteady, apparently transparent, and uncertain in position, and the light, if good, 
shows dazzlingly bright. On the other hand, if the eye looks chiefly at the hair the light shows 
simply as a fairly bright background against which the hair appears densely opaque, black, sharp, 
and clear, and its position relative to the center of the light is unmistakable. No amount of 
focusing for parallax seems to prevent this result, which is acknowledged by every observer I 
have ever known to try it. 

No table of results is given regarding the setting of new jwints ahead on the line for the 
reason that these results are very uniform in character, and seem to depend scarcely at all either 
on the length of the foresight or the backsight. Even on lines 30 miles in length independent 
settings with the telescope in the same direction seldom dittered over a few inches, though in 
reversed positions they sometimes differed as much as 10 feet. The collimation error was very 
variable, owing to the jolting the instrument continually suffered in rough country. Curiously 
enough, in the longest shot of the whole survey, about 80 miles, the four settings agreed exactly. 
After the experience of the first tangent the foresights were made as long as possible, there 
seldom being more than two or three prolongations even in the longest tangents. 



Appendix No. 2. 
Report of Mr. E. L. Ingram, assistant engineer, on monument location. 

San Diego, Cal., October 31, 189i. 
General constants. — The following constants enter more or less into all the formuhii adapted 
to the work in hand, and are here grouped together for convenience of reference. 

The geodetic constants conform to Clark's 18GG spheroid. Reference is made to the following 

publications: United States Coast and Geodetic Survey Card, 188G; United States Coast and 

Geodetic Survey, Appendix 7, 1884; United States Coast and Geodetic Survey, Appendix 9, 1885. 

Major semi-axis = a = G378200.4 meters; log. = G.80469857 

Minor semi-axis = i = G356583.8 meters : log. = 6.80322378 



294.98: 293.98. 






Eccentricity = 


=: '11-/2: =e'= 0.00G7G8G5S 
a' 


; log. = 7.83050257 


Sin. 1" 




log. = 4.6855749 


2 sin. 1" 




log. = 4.9866049 


Sin. 31° 47' 




log. = 9.7215704 


Sin. 310 20' 




log. = 9.7160108 


1 meter 


= 3.2808693 feet; 


log. = 0.5159889 


1 meter 


= 39.3704316 inches; 


log. = 1.5951702 


1 kilometer 


= 0.6213768 statute mile; 


log. - 9,7933550 


Ifoot 


:= 0.30479727 meter; 


log. = 9.4840111 


1 statute mill 


! = 1609.3296 meters; 


log. = 3.2066450 


TT 


= 3.14159265; 


log. = 0.4971499 


i sin. 1" 




log. = 4.3845449 


a(l-v') 0335035; 


k.g. = 6.80174898 


1-e' 




log. = 9.9970504 


e'^ sin.' 1" 
6(l-e'0 




log. = 6.4264506 


e-' sin. 1" 
4(l-e-^) 




log. = 1.9169670 


Siu.-^ 1" 
12 




log. = 8.291968."". 



Sin.- 1" log. 

Radius of sphere with volume of Clark's spheroid - 
Radius of sphere with surface of Clark's spheroid = 
Length of meridian (juadrant of Clark's spheroid = 



= 9.3711498 

6,370,991 meters. 

6,370,997 meters. 
10,001,887 meters. 



134 



uniti:d states and Mexican boundary. 



Formulcc for tam/ents and jjaraUels. — Parallels of latitude are most conveniently located in 
tie field by tlie tangent (to prime vertical) and offset method. All necessary couipiitations may 
be made by tlie formulie and tables of United States Coast and Geodetic Survey, Appendix No 7, 
1884, but the formula:' given below are better adapted to the purpose. 
Let L = latitude of parallel and initial point of tangent. 
/ = latitude of any point on tangent. 
M — longitude of initial point of parallel and tangent. 
m = longitude of point on tangent whose latitude is I. 
D — distance on tangent from initial point to point {m, I). 
N = normal to ellipse (meridian section) to intersection with minor axis. 
K = radius of curvature of ellipse (meridian section). 
Z = azimuth (N. to E.) of tangent at point {m, I). 
900 — z — change of azimuth between initial and given points. 
Then 

a (1 — e'-) _ ^ _ a 

:2"Lp72 " ~ (1 _ ,.-• siu:-T:yT2 



■'=ri- 



D' 



90^ - Z = D tan. / 



L (1 + e^ cos- 
N"-M sin. 1"^ 

1 



L) 



M 



N sin. 1 



, or, OOO- Z = (w -M) sin. / 



(lian offset from tangent to i)arallel. 



Argument (metric.) 


Fur nay parallel. 


Constant lor 
31° 47'. 


Constant for 
31° 20'. 


Log.N = 

Log.R = 

Log.(L-J)" = 

Log. (L-!) meters = 

Log. (m-M)" = 

Log.(90o_Z)" = 

(90O— Z)" per kilometer = 


21og.D- 
21„g.D- 
log..D--log. cos I- 
log.(«»-M),log.siu(. 


6.8051067 
6.802973S 
8. 80257 U 
7. 3140232 
1. 4906810 


6.8050964 
6. 8029424 
8. 8101789 
7. 3216616 
1.4906713 


20.02" 


19. 67" 



Back-azimnth error. — The meridian lines for laying off the monument offsets are secured by 
turning oft" from the tangent line an angle depending on the theoretical azimuth at the given point 
and the assumed azimuth error at the same place. The sliortness of the offsets and the smallness 
of the whole azimuth error to be distributed are always such that any reasonable assumption will 
give sensibly the same held location. Wlien the azimuth error is large it is assumed to be constant 
between the heliotrope stations, since intermediate stations exert no influence on the prolongations 
of the line. When the azimuth error is small it is assumed to vary in direct ratio with distance 
from initial point of tangent, since other complications are much simplified without causing any 
practical error in the result. When the tangent error is known at one or more points along the 
line the azimuth error is distributed so as to be consistent therewith, at the same time keeping 
the assumed curvature of the tangent of the simplest possible character. Straight line chords 
joining the heliotrope points are then considered to represent the tangent as run. The assump 
tions thus made with the various tangents appear in the tables in their proper places. By the 
curvature of tlie tangent is meant such a curve as will contain all the heliotrope points (or initia 
points of prolongation) and not the intermediate points which fill out the tangent. By instruction 
even the smallest azimuth errors were distributed on parallel 31° 47', though later in the work 
anything under 10" was ignored. 

Tanrjent error. — By tangent error is meant the deviation of the line marked in the field from 
a true prolongation of the initial direction, as measured on the meridian at the given point. The 
tangent error and back azimuth error must harmonize with each other, the assumptions made for 
one controlling those made for the other. In some cases the tangent error was measured directly 
in the field; in other cases it had to be assumed, being directly computed in accordance with the 
distribution of azimuth error. In every case all the known errors were carefully considered and 
the simplest possible assumptions then made which would include and agree with observed facts. 



UNITED STATES AND MEXICAN BOUNDARY. 



135 



The tables show in detail the assumptions made. When the azimuth error averages one-half 
second or less per mile it may safely be distributed in direct ratio with distance from initial point 
of tangent. In this case the tangent error will vary as square of same distance, and the offset 
formula may be conveniently modified so as to cover this correction. The direct ratio assumption 
for azimuth error distribution gives a smaller tangent error than when the error is divided entirely 
among the heliotrope points. This may be considered rather advantageous than otherwise, 
corresponding to the reasonable assumption that the tangent errors do not occur all one way. It 
may here be noticed that it is tlie curvaiure of the tangent as run (the successive deviation of 
successive prolongations) that modifies the computed offsets to the monument curve, and not the 
absolute value of the tangent error. Hence an incorrect assumption in regard to the value of 
the tangent error is a matter of much less imjiortance than might at first appear. 

Tanyent data. 
[Distances liy chain and .subject to correction; latitudes by J. F. Hay ford, 
TANGENT NO. 1. 



station. 


Offset 

N. 


Latitude. 


Back-azimuth error. | Tangent error. 


Na.e. 


Distances 
tate.^. 


Measured. 


Assumed.* Meas^ured. 


Assumed. 

N.f 




Meters. 
-(1,274.13) 
-(1,077.21) 
- (711.671 


1,035 
1.03 
1.02 


o , „ 




" 1 




















1 




Monument No.2 

Monument No 3 








0.00 





4 262 76 ' 5 no 








0.00 
0.06 
0.33 
0.40 
0.90 

4.14 
4.52 
4.02 
8.09 
9.67 












+ «.0 
+ 12.0 
+ 18.0 
+ 24.0 
+ 30.0 
+ 59.9 






10,934.20 
11,834.85 
16,212.00 
19, 388. 55 
25, 584. 00 
28,233.60 
29,264.50 
29,531.50 
38, 149. 80 
41, 647. 90 
42,890.70 
43, 392. 30 
50, 602. 62 
51,130.35 
52,639.50 
55,277.80 
■ 59,093.28 
59, 137. 18 
79,058.47 
79,061.88 


























1.38 
3.18 














Mexican Astronomical No. 2 


24.77 




.75.0 




1 75.0 
+ 79.0 
+ 83.0 
+ 87.0 

i 93.0 
+ 93.0 
+ 98.0 
+ 107.0 
+ 120.0 
+ 137.0 
+ 159.0 
+ 159.0 

1 186.B 




Heliotrope 29 B 




























10.13 


Heliotrope 43 A 


























Heliotrope S"" A 








14. 95 
16.71 










Monument No 11 


122.46 




19.66 






Monument No 15 


240. 10 
235.98 




R«place(l by tangent 
No ■> 
















■ 



ru 



11 



MonumentNo.il... 

Monument No. !.">.. . 

stronomical No. 2. 



TANGENT NO. 2. 



Zero. 
19, 970. 39 
19, 973. 80 



22.91 
4.14 



.00 I 



TANGENT NO. 



Monument No 15 


—3.41 
Zero. 
1,672.65 
21, 470. 77 
34,658.32 
34,664.01 


4.14 
Zero. 






*0.0 




to. 00 




31 47 0. 21 


0.0 


0.00 


Heliotrode 1 A 


0.0 

+23.4 


0.00 




27.05 
68.40 
60.84 






2.25 


A.stronornicalXo.3 


3146 58.00 


+ 34.8 


4.48 
4.48 


+34.8 













* Assamed coustant between given points. 



\ In direct ratio between given points 



136 



UNITED STATES AND MEXICAN BOUNDARY. 



Tanncnl data — Contiuued. 

TANGENT NO. 5. 



Station. 


Offset 

N. 


Latitude. 


Back-azimuth error. 


Tangent error. 


Name. 


Number. 


Measured. 


Assumed.* 


Measured. 

N. 


Assumed. 

N.f 




Zero. 
5.69 
20,463.36 
21,611.00 
44,«5.U 
44,423.78 


Zero. 
2.44 
22.79 
25.20 
98.97 
63.11 


31 46 58. 00 


0.0 




0.00 






0.0 
+ 1.6 
+ 1-7 
+ 3.4 


0.00 
0.078 
0.086 
0.306 
0.366 


Monument No 3' 








Monument \o. ■ 


















3146 58.55 


+ 3.4 











•Indirect ratio. 








t As 


square uf distance. 





MONUMENT CURVE. 




The diagram i.s intended to indicate the geometrical conditions governing the location of the 
mouumeiit curve joining any two consecutive existing (old) monuments, and is almost self-explana- 
tory. The diagram, as will be seen, shows different conditions, all of which would not exist in 
any one case. The two tangents shown correspond to the two cases of error by which a tangent 
may be affected. The two monument curves represent two cases, depending on which terminal 
monument is farthest north. The computed ottset from the tangent as run to the true parallel 
through one monument is increased or decreased by the distance between the monument curve 
and parallel at the given point, and the distance between the parallel and monument curve is 
assumed to vary in direct ratio as distance from monument at intersection of the curves. 

Theoretical offset formuht, i)arallel 31° 47'. 



UNITED STATES AND MEXICAN BOUNDARY. 



137 



The oflset from taugciit as luii to luouuuieut curve at auy givcu point is made uj) of four parts, 
as follows: 

1. TLeoretical oflset from a true taugeut to a true parallel tlirougli initial i)oiut of tangent. 

2. A correction for tangent error. 

3. A coustaut of translation corresi)ondiug to true parallel tlirougb oue monument. 

4. A propoitioual part of tbe amount by wbicU a true parallel tbrougb one monument passes 
nortb or soutb of tbe otber monument. 

Tbe following table is formed from tbe data contained elscwbere in tbis report: 



Xa^.ent 


0fl80t (by theoretical lurmula-). 


1 


Theoretical— tangent error + 1.12 — proji. part 28.45 


2 


Theoretical (no tangent error) + 4.14 — jirop. part .59 


3 


Theoretical— tangent error +4.14 + prop, part 2.79 


3 


Theoretical - tangent error + 6.93 + prop, part .U8 


5 


Theoretical — tangent error + 2.44 + prop, part .11 


5 


Theoretical — tangent error + 2.63 + prop, part .98 



In these formubv- 



Log. theoret. = 2 log. sta. — 7.3140232, except for tiingunt 2, wh. 
sta. is meant distauoe from the initial jioiut of the taugont. 
Tang, error (Men. 3 to 15) ^interpolate as directed in tangent data. 
Taug. error (Mon. 15 to 21) = zero to sta. li)72.()5 and then log.^' [log. ( 
Tang, error (Mon. 21 to 26) = log.-' [log. (sta. —8134.68) — 3.7728459J. 
Tang, error (Mon. 26 to 40) = log.-' [2 log. sta. — 9.7315917 J. 
Proportional part 28.45 =log.-' [log. (sta. —4262.76) — 3.2849425]. 

= log.-' [log. (19970.39 — 8ta.)—4.5295346] 

= log.-' [log. (sta. + 3.41)— 3.8863124]. 

= log.-' [log. (Bta. — 21470.77) — 5.2172615]. 

= log.-' [log. (sta.— 5.69) — 5.2694635]. 

= log.-' [log. (sta.- 21611.00)— 4.3667876]. 



substitute (sta.) the valu 



sta.). By 



i.9444414]. 



Proportional part 

Proportional part 2.79 

Proportional part .08 

Proportional part .11 

Proportional part .98 



It will suggest itself to anyone that tbe above method of deriving an offset, while being 
the first and natural method, is exceedingly awkward and laborious. In nearly every case tbe 
monument site was selected in the field, and a simpler ])laii was a desideratum. Tbe writer there- 
fore devised by familiar methods the following empirical foiinube, which exactly represent the 
desired curve and will be found to be of exceptional simplicity when put in actual use. It will be 
noticed that only one new logarithm is involved for any given case, and in actual practice less 
than one minute served to determine tbe offset : 



Offset (by empirical formula'). 



log.-i (21og.3ta. — 7.3140232) — log.-i (log. sta.- 3.2849093) + 3.33 — tangent error : 
log.-l [2 log. (19973.80- sta.) —7.3140232J —log.-l [log. (19973.80- sta.) —4.5303464] + ■ 
■E. of sta. 1672.65 = log.-i (2 log. sta. — 7.3140232) + log.-' (log. sta. — 3.88624.14) + 4.14; 
W. of sta. 1672.65 = log.-l (2 log. sta. — 7.3140232) + log.-i (log. sta. — 4.7877796) + 4.33; 
log.-l (2 log. (sta. — 1678.00) —7.3140232] + 8.04 ; 
log.-l [2 log. ;sta. + 55.14) -7.3156868] + 2.44. 
log.-l (2 log. sta. -7.3156868) + log.-l (log. sta.— 4.3645775) + 1.09. 



S. Doc. 2i7- 



-13 



138 



UNITED STATES AND MEXICAN BOUNDARY. 



Augles iu liist and second sketches below subject to correction, depending on distribution of 
back azimuth error of +23".8, and also for changes in distances due to remeasurements. The 
back aziunitii error is assumed to have occurred in three equal parts at heliotrope stations 
(initial points of prolongations) K, 3 I, and 4 L. 

SKETCHEiS ON AZIMUTH LINE. 




The two sketches next above show the assumed di.stribution of azimuth error and the geomet- 
rical conditions governing the offset formula for the field location of the monument line. 



FORMULA FOR AZIMUTH LINES. 

The formula- and tables of U. S. Coast and Geodetic Survey, Appendix No. 7, 1S84, are very 
convenient for short lines and secondary triaugulatiou, but give approximate results only witli 
lines of great length, such as occur on this survey. The following formuhc give results of the 
greatest exactness even ou lines of several hundred miles iu length. 

Given qj = latitude of first point. 

Given A = longitude of first point. 

Given a = azimuth at first point toward second point. 

Given & — distance from first to second point. 



UNITED STATES AND MEXICAN BOUNDARY. 139 

To find f//, A', rt', of second point: 

^ s e- d^ siu.^ 1" 

^ = Tsin.T" + - eir^r^^r ''''^ '^ *'"^- ^'^ 

e'^ /^ ' sin. 1'' _ ^ , ^, 



i(l-e^) 



tan. 4 {,.■ + C- ^ A) =«ii^:Hi^cot.« 
' sm. .J {y—6) 2 



tan. .} («-■ + r + A A) ^ "-f /~^ cot. 



COS. Hk— ^) , 
COS. h{y+d) 

s sin. J («' + r — «) r «' sin.- 1" ..,„,, ,~^ 

The second term for 6 is insensible except for very great values of s. Z is always a very small 
angle, and is to be used with its algebraic sign, a and <r ' + T are angles of polar triangle, and 
not azimuths from south point of meridian, as usually given. 

ft = radius of curvature of meridian at middle latitude. 
r = normal (to minor axis) at first point. 
ti = angle between terminal normals. 
^;K = A' = A; y = 90o^<p. 
Eight places in logarithms give 3 correct in tp ' and A ' and 9 give 4. 

OFFSET FORMULJ3, COLORADA AND PACIFIC AZIMUTH LINE. 

Colorado Eiver to Monument 207: Offset (S.) =log.-' [log. (10910.62 — sta.) —3.3026100J. 

Monument 207 to Station K : Oliset (N.) = log.-' [log. (sta.— 10910.62) —3.3026100]. 

Station K to Monument 220: Offset (X.) = log.-' [log. (sta. — 10012.20) —3.3373.516]. 

Monument 221 to Station 3 I: Offset (+ =N. — = S.) = log.-' [log. (113564.93 — sta.) + 
7.0068280]. 

Station 3 I to 4 L: Offset (+ = K— -^ S.) = log.-' [log. (sta. — 155321.41) +7.1833113]. 

Station 4 L to Monument 252 : Offset (N.) = log.- ■ [log. (215479.85 — sta.) + 7.50892.5(i]. 

Monument 252 to Monument II and Monument II to Monument 258 : Offset — zero throughout. 

By " sta." in these formula is meant station number as given in tables of this report, but the 
reduction to mean sea level must be applied before using in the formula-. These original distances 
were necessarily used because the remeasured values were not available at the time. Eemarks on 
the derivation of these formuhe appear in another part of this report. 

General remarks. — On parallel 31° 47' and the meridian line the duties assigned to my care 
comprised the mathematical and field work of monument location, and the time so employed 
extended from August 15 to November 5, 1892. 

On the azimuth line from Colorado River to Pacific Ocean the work intrusted to my care 
included the mathematical and field work of monument location and superintendence of monument 
erection. Operations on the azimuth line extended from March 20 to June 30, 1894. 

The camp force varied somewhat, but averaged about as follows: Myself, in charge, 1 overseer 
and photographer, 1 wagon master, 1 rodman, 1 cook, 1 cook's heljjer, 2 packers, 3 teamsters, 1 
blacksmith, 5 laborers. 

The camp transportation averaged about as follows: Two baggage wagons, 2 water-tank 
wagons, 1 truck wagon for monumeuts, 1 spring wagon, 1 buckboard, 6 aparejos, 26 mules, and 3 
saddle horses. An extra wagon with 4 mules was under camp control to April 23. 

The formuhe for use with this line, which are in a certain measure empirical, are simply given 
as used, without going into their derivation, which can be readily studied out by anyone duly 
interested. The writer having personally run the line of reference, made the distribution of 
azimuth error according to his best judgment, and as shown in the sketches. All data not here 
given may be found in my report of tangent and line work, offset formulte being based ou original 
stadia measurements reduced to sea level. 

The official limit for north and south difference of monument location between United States 
and Mexican points was placed at 2 meters, which was never reached. United States and Mexican 



140 UNITED STATES AND MEXICAN BOUNDARY. 

distances between all luoumueuts were compared in the tield aud subjected to remeasuremeut if 
dili'ering over 1 in 500. 

Throughout all laouuuieut work iu my charge the ino^t cordial and tVicudly relatious existed 
between the United States and Mexican engineers aud camps. 

Appendix No. 3. 

Eeport of Mr. B. A. Wood, assistant etujinccr, on moniimcnf location. 

Before beiug assigned to duty with the monument party the location aud erection of monu- 
ments along parallel Sl^- 47' bad been completed under charge of Mr. K. L. Ingram, assistant 
engineer, and the methods tliere employed having been found satisfactory tlie same general plan 
was followed with regard to monuments along parallel 31° 20', as the problems here presented 
were practically the same. 

The positions of the old monuments having been determined and their identity established, 
it became necessary to interpolate other monuments iu a curved line conforming as nearly as 
possible to the parallel. In the calculation of these positions the formuhe for the computation of 
geodetic latitudes, longitiules, and azimuths, A[)i)eudix No. 7, Eei)ort of 1884 of the Coast and 
Geodetic Survey, were employed. By a combination of the quantities which affected each tangent 
it was possible to obtain a formula by which the latitude and azimuth for any given distance from 
the initial point of the tangent could be computed iu the field in a few minutes, thus greatly 
simplifying aud facilitating the work. 

The question of the distributio!i of the azimuth error was one that received no little consid- 
eration, as an improper distribution would, in extreme cases, cause a greater discrepancy than the 
limit agreed upou by the joint commission. It was finally decided that such errors not greater 
than teu seconds should be neglected. When the error exceeded ten seconds, the circumstances 
of the tracing of each particular tangent were carefully considered aud the distribution made 
at such points as seemed most liable to be in error by reason of wind, uncertain light, short 
backsight, etc. 

By reference to the report of Mr. E. L. Ingram, assistant engineer, it will be seen that there 
were eight tangents traced along parallel 31'^ 20', viz, 8, <), 10, 11, 12, 13, 1-1, and 13. Of these, S, 1», 
10, and 11 were affected by back-azimuth errors of less than ten seconds, while the errors of 12, 13, 
and 14 were 12.G", 32.3", and 32.9", respectively. That of 15 was not measured directly, but 
was obtained by triangulation and found to be less than teu seconds. 

The errors of tangents 8, 9, 10, and 11, being less than teu seconds, were neglected; the error 
of tangent 12 was distributed equally at each azimuth station; the error of tangent 13 was 
distributed at three stations that seemed most liable to be iu error, and the error of tangent 14 
was distributed through the whole length of the tangent. 

It may be interesting to follow the successive steps by which the tiiuil results were obtained. 
The following table shows the results along tangent 13, the data for wliicli are given in the report 
of Mr. E. L. Ingram, referred to above. A sketch of tangent 13 is also given showing the relation 
of the monumeut curve to the astronomical parallel, etc. 



UNITED STATES AND MEXICAN BOUNDARY. 



141 



United Ktates tangent 13, parallel 3P' 20' X. 

Measured distance from tangent to parallel +14.51 

Initial point of tangent north 151 53 

166. 04 

Computed offset for 42,149.68 meters 84.71 

Error of line to N 4.92 79.79 

Difference of station error, north 86. 25 



Monnmont Xo. or 



i C'OE) 


8. 




5, 003. 






10,308. 
12, 035. 


2 












■'2 292 








31 715 


08(22E) 

(19 


33,24.5. 
3B,g04. 


KiiK) 

7...St,n.ll_ 


42, 152. 
42 149. 



lO 00.0 

9 59.8 

S 21.6 

1,865.43 50 45.!) 



Observed 

back- 
.ijiiniith. 


Com- 


:. ■, „ 


+ 0.00 




+ CO 






89 56 56.7 


+ 4.64 


50 58.8 


+ 5.07 


56 35.6 


+ 0.91 




+14.02 




+18. 14 


Aild 32.3" 

to the 

theoretical 

back-azi- 

mutli. 


+23.70 
+39.51 
+47.96 
+52. 70 
+64.59 




+76.81 




+84.72 


89 46 4.1.2 


+ 84.71 



Line ;'^'";f"' 
error. pjvrallel. 



-151.53 
-151.33 
-151. 53 
-151. 53 
-151. 53 
-151. 53 
-151.53 



-151.53 ] +45.61 

-151.53 i +58.90 

-151.53 1 +64.89 
-151.53 ; 



+68.03 
+75. 31 



+86.25 
+86. 25 



—151. 53 
—151.51 



— 84. 03 

— 35. 95 

— 41. 96 

— 34. 33 

— 15. 71 
+ 2.80 
+ 14.52 
-I 14.51 



+ 143.89 
+109.48 
+ 75.98 
+ 72.92 
+ 61.02 
+ 25.79 



— 54.38 

— 63.82 

— 68.72 

— 71.03 



73. ( 



Tangent 



Note.— Tlie azimuth i 



utrate<l at 100, 101, and 102, and distributed directly as the distance. 



142 



UNITED STATES AND MEXICAN BOUNDARY 



1 



UNITED STATES AND MEXICAN BOUNDARY. 143 

Ou June 14^, 1893, tbe preliminary coinputatious having been completed, I went to ISTogales, 
Ariz., for tbe purpose of comparing tlie data with the engineers of the Mexican section. This duty 
completed, on June 10 the position of Monument No. 122 (old Monument No. 26), situated on the 
north side of International street, in the town of Nogales, was marked and its erection commenced. 
From this time until September 19 the erection of monuments along parallel 31° 20' progressed 
continuously, during which time there were erected 7-1 monuments, consisting of 13 masonry, 14 
sectional iron, and 17 solid iron, in eighty working days. 

The average force employed for this work consisted of the following men and transportation, 
viz: 1 quartermaster, 1 photographer, 1 blacksmith, 1 stone mason, 2 rodmen, 5 teamsters, 5 
laborers, 1 cook, and 2 helpers; 1 spring wagon, 1 buckboard, 2 water wagons, 3 baggage 
wagons, 1 truck, 5 horses, and 24 mules. 

Parallel 31° 20' having been marked, on September 21 I returned to Tucson, where prepara- 
tions were commenced for the continuation of the erection of monuments along the azimuth line 
between the western extremity of parallel 31° 20' north and the Colorado Eiver. The wagon train 
traveled overland and did not reach Tucson until October 7. 

On November 17, 1893, in accordance with instructions, I again went to Nogales, Ariz., for 
the purpose of comparing data with the engineers of the Mexican section and of entering into the 
final agreement which should govern the location and erection of monuments between Monument 
No. 127 — the western extremity of parallel 31° 20' — and Monument No. 108 (old Monument No. IX), 
situated about 4 kilometers northwest of the town of Souoyta. This agreement was afterwards 
extended so as to include the entire line to the Colorado Eiver. This duty concluded, I went to the 
camp previously established in the Sierra de los Pajaritos, near the old mining camp of Warsaw, 
and on November 22 tbe work of erection was commenced. 

The beginning of this work presented greater difficulties than any other portion of tbe entire 
line, situated as it is in mountains over which it was necessary to pack monuments and materials 
over rugged trails for a distance of about 18 miles. In order to give some idea of difficulties 
encountered in this particular section, there were consumed fifteen working days in erecting the 
7 iron monuments included within the first 35 kilometers. No mention is here made of tbe 2 
stone monuments in the above distance, as they were built by a special gang. 

After these mountains were passed much greater progress was made, and 68 iron monu- 
ments were erected in seventy-seven working days, and for tbe whole line there were erected 10 
masonry, 15 sectional iron, and 53 solid iron monuments in ninety-two working days. 

The party as organized for this work consisted of the following men and transportation, viz: 
A quartermaster, photographer and overseer, wagon master, blacksmith, stone mason, rodman, 
teamsters, 8 laborers, 2 cooks and 2 helpers ; 2 spring wagons, 1 buckboard, 3 water wagons, 5 
baggage wagons, 1 truck, 5 horses, and 36 mules. 

From the above it will be seen that tbe force employed ou the azimuth line was larger than 
that employed on parallel 31° 20'. This was rendered necessary on account of the greatly increased 
distance to points of supply of all necessaries, including materials, provisions, and water. 

The erection of Monument No. 153, on Cerro de la Lesna, was attended with peculiar diflflculties. 
The summit of this mountain is a sharp ridge of rock, which rises 36 meters in height, with almost 
perpendicular sides, over the top of which the line passed. Eodman Wheeler was the only man 
of tbe party who could scale tbe wall. He fastened a rope, by means of which others ascended 
and they pulled the materials for the monument up after them. To add to the difficulty the 
summit of the ridge was not of sufficient width to support the base of the monument, and had to 
be levelled by blasting. Five days were consumed in erecting this monument. 

Other obstacles were encountered in the Sierra del Tule and the Sierra de las Tinajas Altas, in 
which places it was impossible to obtain practicable trails for mules, and the materials and tools 
bad to be transported by baud over long and difficult ascents. 

The engineering problem here presented was somewhat different from that affecting the two 
parallels, aiul resolved itself into simply interpolating new monuments in a straight line between 
old monuments, previously identified and located, and whose positions had been computed by Mr. 
John F. Hayford, assistant astronoraei', who traced the line. 



144 UNITED STATES ANIJ MEXICAN BOUNDARY. 

The limit of -! meters, as fixed b^ the engineers in chief, was exceeded in two places, viz, on 
the (Jerro de la Lesna and in the Sierra de las Tiuajas Altas. With regard to the first, the difi'er- 
ence disa^jpeared when the line was retraced jointly by Captain Martinez, engineer in charge of 
tlie Mexican section of monument location party, and myself, a special report of which was sub- 
mitted and approved. At the second point the limit was exceeded by only 4 centimeters, and after 
a long discussion of all the facts Captain Martinez and myself considered it to be to the interest 
of the work to accept the diHcrence and j)rocee(l with tlie erection. Utlierwise it would have been 
necessary to retrace nearly 1G3 kilometers of line, involving a delay of two or three weeks, in a 
locality where water was scarce and ouly a sufticient am(mnt obtainable to complete the work 
without unnecessary delay. 

Our position in this matter was further strengthened by a comparison of the results obtained 
by both sections. The angle at Monument No. 175 (old Monument No. VI), between the line of 
Monument No. 1(58 (old j\Ionument No. IX) and Moiuiment No. 17.5 produced, and the line of Monu- 
ment No. 17o-Monument No. 204 (old Monument No. II), as determined by the United States 
section, was 54' .50.5"; as determined by the Mexican section it was 55' 03", or, briefly: 

Monumeut No. 204, north of line Monument No. 168 to Monument No. 175 proiluocd U .5(1. .5 

Mounmont No. 201, north of line Mouunwnt No. 168 to Monument No. 17.") ].ro<lnec<l '. ,^)5 O.'?. 



From Monument No. 175 to the jioint in question the distance is 89,017 meters, from wliieh w( 
»l)tain : 

Log. 80017 = 4.0538-ilS 
Log. tan. 1" := 4.C855749 
Log. 3.5 = 0.5440G80 



0.1834847 



Which gives 1.5.'> meters as the amount <d' divergence between the two lines, wliich, from the 
discrepancy measured of 2.01 meters, leaves 0.51 as the amount of dilferenee in tracing Ihi^ line by 
the two parties. 

In comparing the distances between monuments witii the^ engineers of the Mexican section 
discro|iaiieics were found to exist in the distances as determined by the two sections, amounting 
lo L'oo (II- ;',(io meters in some cases. This, of course, involved a reiueasurement of a portion of the 
line. These remeasnrements were made either directly, with a .50-meter steel tape, or by a small 
triangnlation where the conditions were unfavorable for direct measurement. 

In making remeasurements by triangnlation small Brandis transits were used with veiniers 
reading to twenty seconds. It was surprising to note with what accuracy angles could be measured 
with these instruments. From the results obtained we were convinced that with care and iintience 
angles could be measured within an error not exceeding ten seconds. 

On the line in question it gives me i)leasure to state that only one error in excess of the limit 
was found in the distance as previously determined by the stadia measurement of the liiited 
States section. 

The work on the above line was completed on March 14, 1804, and on the 15tli camp was 
moved to Yuma, where prei)arati()ns were commenced for the continuation of the work westward 
to the Pacific. 

On March 20 I was relieved from duty with the monument party, and instructed to re])ort for 
duty at the head(iuarters of the commission at San Diego. 

The friendly relations estahli.shed and maintained between the two sections for many montlis 
in the field rendered an otherwisi^ arduous duty more than pleasant. To Capt. Caspar Martinez 
Ceballos, Sefior Gama, and Senor Eancalari the writer owes many thanks for their willingness to 
assist and share in many difficulties and hardships. 

And in our own section much credit is due Mr. D. E. Payne, photographer and overseer, and 
Mr. M. E. Cunningham, wagon master for their zeal and efficiency in performing their respective 
duties and thus aiding no little in the successful completion of the above work. 



UNITED STATES AND MEXICAN BOUNDARY 145 

Appendix No. 4. 

h'iptirt of J. F. llayford, iinninlaiit <(stronomer, on line (Icterminationx lichrecn Colorodo h'ircr 
and Xogalc.s, Ariz. 

San Diego, Cat.., December :.'(i, 1S!)3. 

The party assigned to line work left Ynnia, Ariz., for the field on March 14, IS',).",, iind leachcd 
Tucson, Ariz., from the field on September 15, 1S93. Between those dates ICfi points were located 
oil the bonndaiy between Jlonuments Nos. 204 and 127, a distance of 37.3 kilometers. This portion 
of the boundary was already fixed upon the ground by 13 extant Kmory monuments. The field 
work consisted of the location of intermediate points oil the straight lines joining successive monu- 
ments, the measurement of tlie angle at each monument between adjacent monuments, and of 
establishing a connection at the beginning and end with the triangulation already executed near 
Yuma and near Nogales. When combined with the stadia measurements of distances along the 
line. :is m.ide by the topographical party under Mr. J. L. VanOrnura, assistant engineer, the work 
(pf llic line party serves to determine the geographical coordinates of each of the old monuments 
;is well as to locate the new intermediate i)oints. 

The line party proper consisted of myself as observer in charge of the party, 3 heliotropers 
(<inc usually acting as cook), and a driver. The line party was always with or near the topo- 
graphical party, and the sup]ilies and transjwrtation were in common with that party. 

The instrument used was Fanth repealing theodolite No. 725, which h;id previously been used 
for deterndnations of azimuth, and is described fully in that connection. The borizontnl circle, 25 
cm. (10 inches) in diameter, is graduated to five-ndnute spaces and is read by two opposite 
verniers to five seconds. The telescope has a focal length of 41 cm., and an objective 45 mm. in 
diameter. The eyepiece magnifies about :i(t diameters. One tuin of the eyepiece micrometer is 
12.3.73", or one division on the micrometer head is 1.24". 

Heliotropes were used as signals almost entirely, and also furni.shed a ready means of 
comniuidcation between the observer and the heliotropers. 

The line was established in sections, each of as great length as jiossible, on wliicli all iwints 
were estaldished by running toward a lixcd ]>oint. The iVont hcliotroper having placed his 
liclioli(i|.c over a distant point on the line, and the iiistru ncnt being at a known point, a second 
hciidtiiipcr placed himself approximately on line between the in^t^nMlCMt and the front hcliotroper, 
near the proposed site of a station, and sliowcd a light to tlui instrument. The small angle 
between the two heliotropers was then measured with the eyepiece micrometer. The observer 
next telegraphed the result to the near heliotroper, using the Morse alphabet by long and short 
flashes from a heliotrope kept at the instrument for that purpose. The message as received Ijy 
the heliotroper indicated to him how many divisions of micrometer he was from the line, and in 
what direction. Knowing that each division was eijuivalent to mm. per kilometer of distance 
between him.self and the instrument, he converted divisions of micrometer to linear nieasurement, 
using his best judgment as to his distance from the instrument. This measurement hi' made upon 
the ground with a 20-meter steel tape, and placed his heliotrope at the new position. The process 
of measuring the angle between the two heliotropers and telegraphing the result was then 
repeated. 

The first offset, as measured by the heliotroper, necessarily corresponded to the difference on 
the micrometer indicated l>y the first and second messages from the observer, and therefore served 
(o dcfermine the distance from the heliotrope to the instrument. Using this known distance the 
helidiKipcr computed the offset necessary to place him on the line, and again placed his heliotrope 
by nieasurement. This process was repeated until the angle between the two heliotropes was 
ai)parently less than two divisions of the micrometer. 

The final nieasurement of the angle by 27 pointings with eyepiece micrometer on the 
heliotrope ended the operations for that station. The pointings were taken in .sets of three 
alternately on each light. As soon as the measurement was completed, " (). K." was sent to the 
near heliotroper, and he proceeded to mark the station and move on to the next. 



146 UNITED STATES AND MEXICAN BOUNDARY. 

Whenever coiiveuieut, as determined by the topography, position of camp, means of trans- 
portation, etc., the instrument was moved forward to some one of the newly determined points 
and the process of lining in points ahead was continued. In some cases the points, about 2 
kilometers apart on an average, were lined in ahead from a single station for as much as 14 kilo- 
meters. In other cases the instrument was moved up at every station, so that it was never more 
than about 3 kilometers from the point being set. 

In a few cases the instrument was lined in between two known points, one ahead and one 
behind, but this plan was avoided as much as possible because it was much slower than the usual 
method. 

After the heliotroper first showed his light near a proposed station, the time required to place 
his heliotrope within two divisions (2.5") of the line and to make the final measurement of tlie 
small angle by 27 micrometer pointings was usually from thirty minutes to one hour. Jlucli more 
time was spent in traveling to and from stations than was required for the actual instrumental 
work. 

The final measurements of the small angle between the two heliotroper. made it possible, by 
the use of the distances afterwards determined by the topographical party, to compute the small 
oft'set from the station as placed to the true line. These small ott'sets were computed and furnished 
to the monument party. 

The first extant monument from Monument No. 11 (204) near the Colorado was Monument No. 
VI ^175), 1G3 kilometers to the eastward. Before the line party began its work, a reconnaissance 
party, under Mr, .7. L. Van Ornum, assistant engineer, had, by the use of engineer's transits, 
placed a point on the Tinajas Atlas Mountains as nearly as possible on the straight line joining 
Monuments II (204) and VI (17.'J). The front heliotroper was placed at this jioint, Station 
XXXVIII, and the line was run toward it from Monument No. 11(204), a distance of 73 kilo- 
meters. With the instrument at Station XXXVIII, and with a heliotrope at Monument No. II 
(204) as a backsight, the line was produced by a single sight to the most distant visible point 
on the line, Station LI I in the Tule Mountains, 25 kilometers ahead. The intermediate points 
were then located by running toward Station LII. From Station LIl the most distant visible 
point on the line ahead was Station LIV, but 4 kilometers away, on the same range of mountains. 
Prom LIV again there was no chance to take a sight longer than 4 kilometers, to Station LVI, on 
the same range. At LII and LIV the original line was produced. At LVI the line was turned 
to run directly to Monument No. VI (175) as a foresight, and the small angle measured. In eacli 
of the cases in which the line is said to be produced there was in fact a small outstanding angle 
in the line which was measured with the micrometer. These five sections represent the longest 
sights possible in running the line, for in each case the forward sight was taken to a station which 
was against the actual sky line as seen from the preceding station. 

The computation of offsets showed that Station XXXVIII was 0..S7 meter north of the straight 
line joining Monument No. II (204) and Monument No. VI (175). The greatest offset from any 
station on the line as run to the straight line joining the monuments was 0.99 meter to the 
southward, at Station LV. 

From Monument No. VI (175) to Monument No. 27 (127), with one exce])tion, each monument 
was visible from the preceding one, and the line was located by running forward from cacli 
monument to a heliotrope placed on the next monument. 

From Monument No. XII (100) the view to Monument No. XIII (150) was shut out by a sharp 
peak of the Lesna Mountains, about 33 kilometers from Monument No. XII (100) and l."> kilo- 
meters fiom Monument No. XIII (150). This peak, although not high, had faces so nearly vertical 
that it was difficult to climb. It was found on a preliminary investigation that at the point where 
the line crossed the peak the top was so narrow and so unsafe that it would be dangerous as well 
as extremely difficult to place the theodolite there. Accordingly the theodolite was placed 
successively at two points, which maybe called A and B, about 10.") meters apart on a rocky 
bench on the south side of the peak, and the angle at each point between Monument No. XII (100) 
and Monument No. XIII (150) was measured with the micrometer. The linear measurement 
between A and B, in connection with the angular measures, showed that the line was about 25 
meters to the northward of the northern point, A. This measure was then made with considerable 



UNITED STATES AND MEXICAN BOUNDARY. 147 

difficulty along the dobris at the foot of the west vei-tical face of the peak, aud Station XVI was 
established. Afterwards Station XVII was placed accurately on the line Monument No. XII (IGO) 
to Station XVI produced on the top of the peak, and Station XVIII was placed near the east 
foot of the peak accurately on the line Station XVII to Monument Xo. Xltl (1.50). 

All pointings upon Station XVII were made upon a short 1-inch pole held in position by hand, 
and the station was marked by a cross cut in the surface of the rock. The intermediate points 
were put in between Monument No. XII (100) and Station XVI and between Station XVIII and 
Monument X^o. XIII (150) in the usual way. The angles at Monument Xo. XII (160), between 
the back-sight (jNIonument No. X [102]) and each of the points Station XVI, A, and B, were 
measured with micrometer, and also the angles at Monument No. XIII (150), between the fore- 
sight (Monument No. XIV [I4GJ) aud each of the points Station XVIII, A, and B. These, 
measured, gave three of the four angles of each of the four-sided figures — Monument No. XII 
(IGO) to Station XVII, Monument No. XIII (150) to A, and Monument No. XII (160) to Station 
XVII, Monument No. XIII (150) to B — ^and therefore from each figure there was derived a value 
for the angle at Station XVII between Monument No. XII (160) and Monument No. XIII (150). 
These two vaules were 180° 21.5" and 180^ 19.2". The mean, in connection with the stadia 
distance along the line, gave for the offset from Station XVII to the line joining Monument No. 
XII (100) and Monument No. XIII (1.50) 0.91 meter south. 

This procedure gave a strong azimuth connection past the difficult point, and gave the 
ditterent otfsets independently of the rough linear measurement along the debris on the west face 
of the peak, which served for the first approximate location of the line. The com])nted value for 
the offset at Station XVII is i)robably as accurate as would have been obtained if that station 
had been occupied in the usual way. 

If the lines Monument No. II (204) to Monument No. VI (175) and Monument No. XII to 
Monument No. XIII, which could not be run with a single foresight, be omitted, there are but 16 
cases in which the eomxiuted offset from the station as set to the line joining adjacent monuments 
was greater than 0.10 meter, and the greatest offset was 0.31 meter. 

The azimuth of the line Monument No. II (204) to Station XXXVII was determined by the 
Yuma triangulatiou. (See astronomical report.) All the angles in the line as run were measured 
with the micrometer, save the angle at Monument No. VI (17.5). That angle, being too large (55') to 
measure witli the micrometer, was measured with the theodolite used as a repeater. The instru- 
mental lino was finally connected with the line B to No. 7 of the Nogales triangulatiou (see 
astronomical report) by measuring with the theodolite used as a repeater the angle at B between 
Monument No. XVIII (129) and No. 7. The azimuth of the line B to Monument No. XVIII (129) 
as computed from the Yuma triangulatiou and the measurement of angles along the boundary was 
6.7" greater than the azimuth as given by the Nogales triangulatiou. This difference of 0.7" 
arises from the errors in the Yuma and Nogales azimuth observations, the errors of the Yuma and 
Nogales triangulations, and the measurement of 16 angles along the line. 

The computations of geographical positions were made as follows: The distance on the Clark 
spheroid between Monument No. II (204) and ]VIonument No. 27 (127) was first computed from the 
latitudes and longitudes of those two points as given by the Y'nma aud Nogales triangulations. 
This distance as thus computed may properly be called the astronomical distance, as it depends 
ultimately upon astronomical observations at Yuma aud Nogales. The distance from Monument 
No. II (204) to Station XXXVII on the Tinajas Mountains was determined by the Yuma triangu- 
latiou. This being subtracted from the astronomical distance between Monument No. II (204) and 
Monument No. 27 (127) gave the astronomical distance from Station XXXVII to Monument No. 
27 (127). The direct stadia measurement by the topographical party gave for the distance between 
Station XXXVII and Monument No. 27 (127) a value exceeding the astronomical distance by 
301.85 meters, or one part in 994. The stadia distances on each separate section of the Une 
between those points decreased in that ratio to agree with the astronomical distance were theu 
taken as the true distances between the monuments. 

Using these distances, the known latitude, longitude, and azinuitli at Monument No. II (204) 
and the measured angles along the instrumental line, the geogra])hical position of each monument, 
aud the azimuths of each section of the instrumental line were computed. This computation 



148 



UNITED STATES AND MEXICAN BOUNDARY. 



developed the ac.cnninlated aziumtli error <if G.7" iiiejitioned above. The error was distributed by 
ai)i>lyiiij!: a correlation of 0.C7" to each of tlie ten angles at Monuments No. VI (175), IX (Hi3), X 
(102), and XII (KJO) to XV'III (i:^'.)), and the computation of geograpliieal positions and azimuths 
made again with tlie corrected angles. 

In these computations all lines except Monument No. II (204) to Monument No. VI (17.5) and 
Monument No. II (-204) to Monument No. 27 (127) were computed by the fornuihe and factors of 
Appendix No. 7, Coast and (ieodetic Survey Report for 18S4. Tlu' long lines named weie 
(ioraputed by the more accurate fornuila' of Appendix No. !•, Coast and txeodetic Survey Iteport 
for 188.'). 



IltoVI 

VI to IX 

IXtoX 

XtoXII , 

XII lo xm.... 
xiirtoxiv ... 

XIV to XV 

XV to XVI 

XVI to XVII... 

XVII to XVIII 

xvm to XIX 

XIX to 27 



162, 970. 5 


102, 918. 9 


31, 352. 9 


31,319.6 


23.435.2 


23,409.9 


7. 280. 4 


7, 281. 4 


40, Ml. 5 


40,550.2 


19,881.0 


19, 859. 


27,580.2 


27, 548. 7 


14,759.3 


14,741.8 


4,230.8 


4,231.8 


28,981.3 


28, 940. 5 


.5,047.3 


.5,040.3 


394.1 


393.0 



290 08 30 



20 50 
24 30 
20 20 



The latitude of Station P., as thus computed tlirough tlie wliole Hue, is M° 19' 59.24", and 
from the Nogales triangulation is .il ^ 20' (t;5.70". Tlie difl'ercnce, 4. 1(i", re[iresents the difference 
of station errors in latitude between Monument No. II (-04) and Station B. 

The longitude of Station B, as computed through the line, differed from its longitude from the 
Nogales triangulation by 2.01". Tiiis difference is the indirect effect of the latitude station error 
upon the computation, and not station error in longitude, for the measured distances had already 
been corrected to agree with the astronomical distance. 

The latitude station error, 4.40", and the longitude difference, 2.01", were distributed propor- 
tionally to the distances of the various monuments from Monument No. II (204). 

(Note. — The linal results for the latitudes, longitudes, and azimuths of these old monuments 
computed from the mean of the measures of distances and angles, made by both United States 
and Mexican sections, and the latitudes corrected to conform to the mean latitude of the whole 
boundary, will be found in Report of Joint Commission, page 99.) 

The offsets from each monument to the straight line joining Monument No. II (204) aiul 
Monument No. 27 (127) were then determined by computing the latitude and longitude of a point 
on said straight line opposite each monument. The offsets irom the straight line to each monu 
ment, at right angles to the straight line, are as follows, all to the southward: 

Monument No. VI (175) 1,413.2 

Monument, No. IX (168) 1,18X6 

Monument No. X (162) 1,023.8 

Monument No. XII (160) 974. 9 

Monument No. XIII (l.'.O) 657. 7 



Mouument No. XV (141).... 
Monument No. XVI (137). .. 
Monument No. XVII (136).. 
Monuni-MitNo. XVIII (12S). 
MoniimoMt No. XIX 



Monument No. XIV (146) 540.8 I 

On the whole line the work was pushed forward at all times without reference to favorable or 
unfavorable conditions for accurate observation. It was considered that such a procedure would 
give all needful accuracy, and that economic considerations would not Justify any additional 
expenditure. Much of the observing was done under conditions that at first sight would .seem 
likely to lead to large errors, and it is therefore more than usually desirable that the accuracy of 
the determinations should be put in evidence. 

A study of the method of work and of the instrument leads one to the conclusion that the 
errors in the location of the various points on the ground arise almost entirely from two causes, 
lirst, instability of instrument during ob.servations, and, .second, errors of i)ointing. 



UNITED STATES AND JIEXICAN BOUNDARY. 149 

Inasmuch as the instrument was simply mounted on its own tripod, and was witiiout protec- 
tion from sun or wind, it was subject to irregular movements due to its e.\i)osure. The routine of 
observation was especially designed to cancel out the effect of such movement upon tbe result. 
The mean time of the jwintings on each of the two points concerned in any determination was 
made as nearly identical as possible and the pointings were taken in rapid succession. The 137 
pointings constituting the linal determination of a point were made iu from ten to tbirteen 
minutes. An idea of the magnitude of the errors ainsing from this cause can be gained by noting 
tbe average ditterence between each set of observations and the mean of the sets, as stated later 
iu this report. 

The value of one division of the striding level was 3.68." The level was applied so often, and 
the inclination of the line of sight was usually so small, that the errors from this source must be 
almost inappreciable. 

By "errors of pointing," as used above, must be understood, not only the errors made in 
attempting to place the observing thread upon the brightest point of the heliotrope light as seen, 
but also the errors arising from the assumption that the apparent position of said brightest point 
coincides with the actual center of the heliotrope mirror from which the light issues. 

From Jlay 8 to the end of the work a record was kept during ol)servations of the apjiearance 
of the heliotropes, of the temperature, and of the apparent diameter of the heliotrope light as 
measured in divisions of the eyepiece micrometer. 

The temperatures were taken with a centigrade thermometer jilaccd iu the most extensive 
shade available in the vicinity of the instrument, which was usnnlls tlic little shadow cast by the 
instrument box. There are but few cases in which the recorded temperature at observation is 
below 25° C. (77° F.). During June and July the greater number of the recorded temperatures 
were between 35° 0. (95° F.) and 43° C. (109° F.\ In a single case, on June 24, between 1 and 2 
p. m., the temperature indicated by the thermometer hanging iu the shade of the instrument box 
was 48° 0. (118° F.). 

The apparent diameter of the light of the heliotrope in divisions of nucrometer (each 1.24") 
varied from live or six divisions, in a few rare cases, either early iu the morning or under a clouded 
sky, through the intermediate values to the other extreme, when the apparent diameter was 104 
divisions. This last case occurred between 11 and 12 on a very hot July day on a line of sight 
about 2 kilometers long, which was within 3 meters of the almost bare sand. The average appar- 
ent diameter of the heliotrope lights for the season was twenty-five divisions (31"). 

The diameter of light as measured includes only what might be called the solid part of the 
light, and excludes the rapidly changing rays and spots of light which sometimes formed a 
further irregular extension. 

The principal mirror of the heliotrope, called in this report "R," was round, with a diameter 
of 10 centimeters, and that of the heliotrope called "G" was round, with a diameter of 7.5 centi- 
meters. If the mirror itself were seen with the telescope, it would appear as an ellipse with the 
major axis equal to the diameter of the mirror. The measured angular diameter of the light as 
seen, taken iu connection with the known distance to the heliotrope, shows that the mirror itself 
was visible only on very rare occasions even when the conditions were favorable. tJsually the 
apparent width of the object upon which the pointings were made was many times that of the 
heliotrope mirror. For example, iu the case in which the light appeared 104 divisions in diameter 
it corresponded to a target 1 meter iu diameter, placed iu the position of the heliotrope 1,000 
meters fi-om the instrument, although the diameter of the mirror was only 7.5 centimeters. On 
May 15, with the temperature iu the shade 39° C. (102° F.), a heliotrope mirror 10 centimeters in 
diameter, 43 kilometers distant from the instrument, showed as a blaze of light 44 divisions (55") 
iu diameter, corresponding to a target, in the position of the heliotrope, 11.4 meters iu diameter. 

The characteristic appearance of the heliotrope light, as seen during the observations, over 
highly heated and nearly bare sand or rocks, was a bright blur of light with outline but poorly 
defined. Each separate portion of the outline seemed to be vibrating violently. Usually there 
was a iiart of the blur considerably brighter than the remaining portions, and the brightness 
increased gradually from the outline inward toward this region. In the most frequent case this 
bright region was in the center of the blur, and the extent of the vibration on all parts of the 



150 



UNITED STATES AND MEXICAN BOUNDARY. 



outline was about the same. It frequently occurred, however, that the outline was decidedly 
unsymnietrical with respect to the brightest region. In those cases the brightest region was 
always to windward of the center of the blur, and the leeward part of the outline vibrated more 
violently than the windward side, the whole appearance being much like that of flames blown 
sidewise by the wind. 

lu all cases the pointings were made upon the assumption that the actual position of the 
mirror was represeuted by the brightest portion of the blur, and not uecessarily by the center of 
the blur. 

As a rule, the violence of the vibration of the light increased ^vith increase of apparent diaiu 
eter. The size of the light and the violence with which its outline vibrated was apparently 
greater for lines which were near the ground than for high lines, aud less during a steady breeze 
than when the wind blew in gusts and whirls, or when the air was still. Evidently there were 
various other unknown causes producing large and apparently accidental changes in the appear- 
ance of the light. This makes it necessary to base any reliable conclusions upon a considerable 
number of observations at various stations and on many different dates. Accordingly, in the 
investigation as to apparent diameter of light and accidental errors of pointing, of which the 
results are given below, all available observations from May 8 to the end of the work were used. 

The pointings upon each heliotrope were made in sets of three pointings each, taken in quick 
succession. A convenient measure of the accidental errors of pointing is the mean of the 
differences between each of the pointings and the mean of the three. This mean difference may 
be called J 3. 

Variation of apparent diameter of light and of J 3 with the time of day. 



Hours. 


Heliotrope R. 


Hours. 


Heliotrope C. 


Diame- 


Number 
observa- 
tions. 


A3 
divisions. 


Number 
observa- 
tions. 


Diame- i Number 1 . , Number 
ter ill 1 observii- ',i;,„^j„.,„ observa- 
divisions.; tions. d"'i3iou8 ^.^^^^ 


6 7 


12 
18 
19 

I 

42 

24 
32 

21 
16 


^ 


0.78 
.90 
.73 
.94 
1.12 
1.08 

1.05 
1.02 
.68 


11 
21 

24 


6-7 


18 
28 
25 
27 
34 
31 
22 
49 
28 


23 
37 
38 

18 

16 
12 
12 


0.57 ' 11 
.84 27 
74 .11 




7-8 


8-9 ... 


8-9 






.91 
.85 

1.00 
.76 

1.00 

.47 


40 
27 
18 
5 
4 
16 
14 
14 
6 




8 
1 
4 
9 
12 








12 1 


, 


1 2 


•1 































The mean diameter of light for Heliotrope K was 23 divisions {'29") and for Heliotrope C 27 
divisions (34"). The mean value of J 3 was O.SS division (1.09") for "E," and 0.80 division 
(0.99") for "C". 

Very few of the observations were made within an hour of sunrise or of sunset. The table 
shows incidentally the hours most frequently used for observing. 



UNITED STATES AND MEXICAN BOUNDARY. 



151 



Variation of ajiipareitl diameter of light for different distances betivven the theodolite and hdiolrojK 



Heliotrope R. - 


Heliotrope C. | 


Di8 

tance. 


Diame 

ter in 

divisions. 


Number- 
observa- 
tions. 


Dis- 
tance. 


Diame- 
ter in 
divisions. 


Number 
observa- 
tions. 


Kilome- 






Kilome- 






2 


19 




ters. ^ 


41 


7 


3 


23 






37 


44 


i 


13 






31 


22 


5 


24 






24 


15 


6 


19 






23 


21 


7 


27 






26 


16 


8- 


26 






17 


12 


10 


20 


2 




27 


18 


11-U 


26 


18 




16 


4 


15-19 


23 


30 




24 


6 


20-24 


26 


19 


11-14 


24 


10 


25-29 


11 


12 


15-19 


18 


14 


30-34 


17 


7 


20-24 


19 


4 


35-39 


35 


7 


25-29 i 13 


7 


43 


33 


5 


1-2 37 


51 


56 


13 


6 


3-5 26 


58 


2-14 


24 


40 


1 6-9 24 


50 


15-24 


24 


49 


10-29 j 20 


41 


25-56 


20 


37 







Variatitn of A J for different diameters of light. 



Heliotrope E. 


Heliotrope C. 


Diame- 
ter in 
divisions. 


A3 
divisions. 


Number 
observa- 


ter in 
divisions. 


A3 
divisions. 


Number 
observa- | 
tions. 1 


0-5 


0.77 




0- 5 


0,37 1 4l 


6-10 


.58 




6- 8 


.45 


6 


11-15 


.70 


20 


9- 11 


.62 


6 


16-18 


.85 




12-14 


.65 


18 


19-20 


.95 




15- 17 


.64 


19 


21-22 


.84 




18-20 


.68 


24 


23-24 


.66 




21- 22 


.90 


10 


25-26 


.88 




23-25 


.67 


26 


27-28 .92 




26- 28 


.69 


20 


29-30 1 1.15 




29-30 


.70 


5 


31-32 .83 




31-32 


.77 


6 


33-34 .90 




33- 34 


.63 


4 


35 1 .83 




35-37 


.97 


7 


36-38 ! 1.00 




38-40 


.65 


4 


39-44 1.40 




41-44 


1.20 


9 


45-49, 1.12 




45- 49 


1.23 


7 


50-60 1.90 




50-60 


1.54 


11 


61-67 


1.70 




61-104 


1.29 


10 


0-15 


.66 


42 


O-20 


.63 


77 


16-28 


.85 


46 


21- 34 


.71 


71 


29-67 


1.15 


38 


35-104 


1.22 


48 



The table shows that the aucidental errors of pointiug iucrease much more slowly thau 
the apparent diameter of light, in spite of the ftict that with increased diameter there is also 
increased vibration; and shows that, iu so far as accidental errors were concerned, it was safe to 
observe even under the api)areutly abnormal conditions when the diameter of the light as seen 
was from 1' to 2'. 

J 3 eqvial to l.li divisions corresponds to ±2.7" for the probable error of a single pointiug. 



152 



UNITED STATES AND MEXICAN BOiMNUARY. 



The tinal deteniiiuatiou of each statiou liued iu ahead of the iustrumeut consisted of three 
sets of nine pointings each. A convenient measure of the accidental errors of the sets is the mean 
of the differences between the result from each set and the mean of the three results. This mean 
difference may be called J S. The actual relation between A S and J 3 is shown in the following 
table, in which the first column is the mean z/ 3 for the two heliotropes: 



Uivi^iL« 


AS 

divisions. 


Number 
observa- 


A3 
aivisions. 


AS 
divisions. 


Number 
cibserva 
tions. 


0.0-0.3 


0.30 


1 




0.98 




.4 


.45 


12 




.87 




.h 


.80 


3 




1.32 




.0 


.70 


20 




.95 




.7 


.54 


7 


1.5-1.6 


1.05 




.8 


.83 


15 


I. 7-2. 2 


.80 




.a 


.94 


7 


. 0-. 7 


.60 


42 


1.0 


.78 


5 


. 8-2. 2 


___:" 


44 



J8 = (i.02(i (-oiresponds to ±li.l" for the probable error of a single set, and ±1.13" for the 
probable error of the mean of the three sets. 

J S is appaiently proportional to z/ 3, but is about three times as large as would be accounted 
for by the influence of J 3 alone. 

Only a limited time was available Ibr experimental work in the field, but the following 
evidence in regard to the magnitude of the constant or systematic errors arising from the use of 
heliotio])es was secured as opportunities presented themselves: 

On May 8, in the Tule Mountains, a series of observations were made for the purpose of 
determining whether there was any apparent displacement of the light when the heliotrope was 
neglected, and also to determine whether the apparent position of the light coincides with the 
actual position of the lieliotrope mirror. The line of sight passed from one high ridge to anothei' 
high ridge, about -1 kilometers distant, over deep cafions and intervening ridges reaching nearly 
up to the line of sight. Pointings were made in quick succession upon a 1-iuch pole carrying a 
tiag and upon the heliotrope accurately in line with the pole and within 2 meters of it. 

The mirrors of the heliotrope having been adjusted, the observation.s (•(intinucd for fifteen to 
twenty-five minutes before the mirrors were again readjusted. During tlic ohsii \ ations tlie helio 
trope light appeared to be from 4 to 15 divisions in diameter. The whole .scries of observations 
comprise 47 pointings on the pole and 195 upon the heliotrope, extending over a half hour in the 
forenoon and about two and a half hours in the afternoon. The mean result from all the obser- 
vations is that the heliotrope light seemed to be 0.15 division = 0.19" = 4 mm. south of the pole. 
The observations do not show conclusively that there was any apparent change iu the position of 
the light when the mirrors were neglected. If there was any such change it was masked by the 
accidental errors of observation. The accidental errors of pointing seemed to be slightly greater 
when the mirrors were first adjusted than later, when the light had become less bright and 
a[)i)arently smaller. 

On June 7, at Station VI of Line B, 20 sets of observations of 12 pointings each, extending 
over four hours, were taken to ascertain the effect of reducing the mirror on Heliotrope from 7.5 
cm. in diameter to 2.5 cm. Heliotrope was at Station IV, 5,800 meters to the westward of the 
instrument, and Heliotrope R was at Monument No. IX (168), 17,400 meters to the eastward. The 
average ajjparent diameter of the light from Heliotrope was 25 divisions when the full size of 
the mirror was used, and 23 divisions when the light was reduced by passing through a hole 2.5 cm. 
in diameter. The reduced light seemed to be but slightly less bright than the full light. The acci- 
dental errors were as great with the reduced as with the full light. The mean of the 10 sets with 
the full light gave Statiou IV 2.8 divisions north of the line Monument No. IX (1(18) to Station VI 
l>roduced, and the 10 sets with reduced light made it 3.1 divisions north. There was a remarkable 
difference between the forenoon observations and those made in the afternoon. The mean of all 
sets in the forenoon gave Statiou IV 5.9 divisions north of the line Monument No. IX (168) to 
Station VI produced, and the mean of all the sets iu the afteruoou made it but 1 division north. 



UNITED STATES AND MEXICAN BOUNDARY. 153 

The original deteriniutitiou of the position of Station VI from Station IV, on June 5, would make 
Station IV 0.2 division north of the line Jlonument No. IX (168) to Station VI produced. This 
extreme range of 5.7 divisions in the three values corresponds to a range of 0.20 centimeter in the 
position of Station IV. 

This remarkably large range of results led to a special investigation at Monument No. IX 
(108), on June 15, to determine whether there was a systematic difference between forenoon and 
afternoon observations, and whether there was any systematic error due to the position of the back 
glass, wliich was used to reflect the sunlight to the main mirror of the heliotrope when the sun 
was behind the heliotrope from the observer. Eight sets of nine pointings each were taken in the 
forenoon, and fourteen sets in the afternoon. Ileliotrope C was used at Station IX, Line B, 7,700 
meters to the westward of the instrnment and its position compared with that of two flag poles 
nearly on line at Stations X and XI. The apparent diameter of the light during observations 
was from 16 to 24 divisions. Taking the pointings upon the flag poles as a standard, the hehotrope 
appeared to be 0.0 division farther south in the forenoon tlian in the afternoon. During the 
forenoon observations the sun was to the northward of the line of sight, and during the afternoon 
observations to tlie southward. In the afternoon every alternate set was taken with the back 
glass to the southward of the line of sight, and the remaining sets with it to the northward. To 
exaggerate the eftect, if any, the back mirror was purposely placed so that the line Joining the 
centers of the two mirrors made a horizontal angle of about 50° with the line of sight from the 
instrument. The mean of seven sets with back mirror soutli agreed exactly with the mean of 
the seven sets with back mirror north. 

For the purpose of detecting constant errors the line from Station IV, Line E, to Station XV, 
25,800 meters long, was located independently both by lining in points ahead in the usual way, 
and by lining in the instrument between two known points, one ahead and one behind. Errors of 
pointing upon the forward heliotrope will affect both these locations alike. But errors in pointing 
u[)on the other heliotrope will have contrary effects in the two cases, making the located line too 
far north in the first case, and too far south in the second case if the heliotrope appears to be 
farther soutli than its true position. The greatest difference between the two locations at any of 
tlie ten intermediate stations was 32 centimeters, and the average diflerence was 17 centimeters. 
With one exception, all stations as located by the second method were farther south than by the 
lirst method. During the observations for these locations the lieliotropc lij;lit appeared more than 
.id ilivisions in diameter during a third of the time, and on one (iccjsidn ujiiieared 101 divisions in 
diameter. Tiie lines of siglit were usually near the gronnd. Tlierc were several cases where the 
light appeared decidedly unsymmetrical, and the conditions generally were as unfavorable to 
accurate work as on any part of the whole line from tlie Colorado to Nogales. 

As one more evidence of the reliability of the pointings upon the heliotrope, even under such 
unfavorable conditions as those encountered during the season, may be mentioned tlie azimuth 
error of 0.7" as developed in connecting with the Nogales triangulation. The measurements of 
the various angles in the line as run were made upon heliotropes under conditions no more favorable 
than during the other jiortions of the work. 

CIIAPTKi; V. 

TOPOGRAPHY. 

For measuring the distance along the boundary line, three general methods were considered: 

1. Triangulation. 

2. Chaining. 

3. Stadia measurement. 

The method by triangulation is by far the most accurate, but it is slow and expensive, and in 
the present case would have added very greatly to the ditticult ])roblem of providing water and 
supplies for so many different parties. For these reasons, therefore, it was deemed impracticable. 

The method of chaining is cheap and sufficiently rapid, and the work can be carried on under 
conditions of weather when triangulation and stadia work would have to be suspended. It has 
tlie disadvantage of reciuiring more cutting in a timbered country than does the method by 
S. Doc. 247 14 



154 



UNITED STATES AND MEXICAN BOUNDARY. 



Stadia; of not beiog under the eye of au employe of a high grade of intelligence; of giving 
neither heights nor angles, and of being entirely impracticable in a rough, mouutainous country, 
or in one badly cut up by canons, wliich is the case with a considerable part of the country along 
the International Boundary Line, while even in hilly and rolling country it is less accurate than 
the stadia. On level ground and for distances of a few kilometers the chain is possibly the more 
accurate; but these limitations for greater accuracy practically debarred it from use in tiie case 
considered. 

The method by stadia is cheap and rapid; requires less cutting than that by chain; is carried 
on under the eye of an instrument man, presumably of a high order of intelligence; gives heights 
and angles, and enables objects to be located from the line which is being measured; is ordinarily 
more accurate than the chain, and can be successfully used where the chain can not be, experience 
on this survey having shown that the stadia lines over mountains, hills, and canons were more 
accurate than those on level plains and wide valleys. 

It was conditionally decided, therefore, to measure the distances along the boundary line by 
stadia, and to take astronomical observations for latitude, longitude, and azimuth at or near the 
fixed extremities of each of the six sections of the boundary, which would serve tlie double 
purpose of locating these points and of checking the measured stadia distances between them. 
In addition, these measmemonts were also checked in several jdaces by triaugulation. 

That there should be, however, no question as to the relative accuracy or adaptability of chain 
and stadia for this work, and as each would serve as a check on the other during the earlier stages 
of the survey, when all observers were inexperienced in working under tlie conditions then 
existing, it was decided to measure the entire distance along tlie boundary on parallel 31° 47'— 
159,193.4 meters— both by chain and stadia, and then from the experience so gained select the 
method best suited for the survey. 

The distance thus measured was i)eculiarly favorable for chaining, being in general Hat and 
destitute of trees. The greater part of this distance had been covered by a well planned triaugu- 
lation made for the Mexican Government by Senores Molina and Gontreras in 1855, and it is with 
their results, being unaffected by station error, that comparisons are made. 

As it is believed that such a comparison of the relative values of the two methods of measure- 
ment, on so extensive a scale and under conditions so identically the same, has seldom been made, 
the results are given in detail in the following table: 

Distanves alomj iianillcl 3V-> 17' determined by triaiuinlation, stadia, ami chain. 



Triaugula- 


Stadia. 


S:^ 


.(Corrected 
chain. 


Error of 
corrected 
chain. 


Meteri. 
19,971.1 

21, 500. 7 
13,192.9 
21,028.8 

22, 819. G 


Meters. 
19, 07U. 4 
21,472.6 
13,170.9 
21,597.9 
22, 812. 5 


1/28530 

1/765 

1/600 

1/700 

1/3214 


Metert. 
19,964.7 
21,474.2 
13, 193. 2 
21,605.3 
22,804.1 


1/3120 
1/811 
1/43976 
1/920 

1/1472 


99, 113. 1 


99, 024. 3 


1/1116 


99, 041. 5 


1/1373 



If, instead of averaging the errors of the stadia and chain on the above five sections, con- 
sidered separately, these sections are taken as one continuous distance, the errors of the stadia 
and chain become 1/lllG and 1/1384, respectively, the very small change being due to the fact 
that practically all of the errors had the same sign. 

From the preceding table alone it would appear that over country of this character tlie cliaiii 
is more accurate than the stadia, but such was not really the case; for during the measurement of 
parallel 31° 47' the stadia six times detected the dropping or addition of a chain length— 20 meters. 
These have been corrected in the preceding table, but would have escaped notice entirely had not 
the chained distances been compared each night with the stadia distances, and remcasuremeuts 
made whenever serious discrepancies between the two were discovered. In every such case it was 
found that the addition or omission of a cViain length had caused the discrepancy. 



UNITED STATES AND MEXICAN BOUNDARY. 155 

The stadia having proved superior to the chain in a region peculiarly favorable to the latter, 
and there being no question as to its superiority in the mountainous region yet to be encountered, 
the use of the chain was thenceforth abandoned. The wisdom of this action became more fully 
confirmed with every day's progress of the work. 

The measured distances along the boundary were used as bases in the topographic work. 
Locations were made principally by stadia, but in some cases by tlie method of intersections. 
Datum points for heights were given by a careful line of levels carried along the boundary from 
the Kio Grande to the Pacific. 

Occasionally the topography was "filled in" from located points by aid of the prismatic 
compass, hand level, and sketching. 

Between the Pozo Verde Mountains and the Colorado River — a distance of more than 323 
kilometers— the region bordering the boundary line is difhcult of access, remote from railroads, is 
practically uninhabited by Americans (there is but one American ranch within 30 kilometers of 
the boundary line on the United States side), and is a true desert, containing but five badly 
spaced permanent watering places in the entire distance. 

Owing to these causes, and in order to expedite the work in this inhospitable region, it was 
decided that between the west end of parallel 31° 20' aud the Colorado Itiver a topographic belt, 
1 kilometer in width, adjacent to the boundary line, would be surveyed and plotted in the usual 
manner; but that the remainder of the 2i mile belt of topograi)hy would be taken by placing flags 
on all of the prominent peaks, ridges, and other natural objects, to be located by the transit man 
engaged in measuring the boundary line. Another transit man would then occupy these positions 
and from them locate all flags in sight. Other important topograi)hical features were then to be 
located either by stadia or by resection, and contoured sketches of the immediate vicinity made. 

Subsequent events justified the wisdom of the plan adopted, for even with this more 
expeditious method there were times when tlie scarcity of the water supi)ly threatened serious 
interruptions to the work, and slower progress would undoubtedly have been fatal to its contin- 
uous prosecution. 

All heights, except those on the line of levels, were obtained by reading tlie vertical angles 
of the points located. For a time aneroid barometers were tried for obtaining heights, and the 
results were checked in each case by comparison with the line of levels. Although great care was 
used, and every possible precaution taken, the results obtained by the use of these baroiieters 
were found to be too unreliable, and their unavoidable errors too great, to admit of their use on a 
work where contour intervals were fixed at 20 meters. 

From the coniMiencement of field work in February, 1892, until its close in October, 1893, Mr. 
J. L. Van Oruum, assistant cngineei-, was in charge of the topographic party, which during that 
period operated between the Rio (irande and the Colorado rivers. From January 24, 1893, until 
September 20, 1893, another topograi)hic party was put in the field under charge of Mr. E. L. 
Ingram, assistant engineer. Tiiis party oi>erated between the Colorado River and the Pacific 
Ocean. 

For the com])osition of these parties and interesting details of their work, see reports of Mr. 
J. L. Van Oruum (p. 160) and Mr. E. L. Ingram (p. 128), assistant engineers. 

The topographic belt proper covered an area of 1,810 square miles, in which there were 39,266 
locations in all— 51 by triangulation, 2,.523 by ti ansit intersections, aud 36,692 by stadia sights- 
each location giving both the position and elevation of the point. 

In addition to those in tlie topi)graphic belt, all prominent mountain ranges and peaks visible 
on either side of the line were located by intersections, giving 2,785 locations of this class. 

The locations by intersections in the topographic belt averaged three sights each, while those 
outside of this belt averaged six sights each. 

Of the area included within the limits of the topographic belt, 360 square miles are covered 
by mountains, 230 by hills, and 1,220 by valleys, mesas, and deserts. 

The average number of locations per square mile for each of these classes is 60, 45, and 6, 
respectively; while the average for the entire topographic belt is a little less than 22 per square 
mile. 



156 



UNITED STATES AND MEXICAN BOUNDARY. 



lu explanation of these figures it should be stated that, as a whole, the iiioiiutains are 
extremely steep and rugged, necessitating, not unfrequently, sights the vertical angles of which 
varied from 40° to 00°. Some of the ranges between the Colorado River and Quitoba(iuita had such 
sharply defined and knife like crest.s that it was with the greatest difficulty their summits could be 
reached, and with equal difficulty, owing to lack of room, that a transit could be set up on the 
crest and readings taken. The iiills are much broken and cut up by innumerable canous, and 
the valleys, mesas, and deserts unusually flat aud very uniform in slope. 

In all, 1,092 miles of stadia liues were run. These Hues were of two classes : 

1. "Main lines," i. e., straight liues run along the tangents or boundary line, and couse(iuently 
free from azimuth errors. 

2. "Side lines," i. e., ordinary stadia lines, in which both angles and distances are determined. 
Of the first class 675 miles in all were run, of which five sections, aggregating 125 miles, were 

checked by triangulation, with an average error in distance of I in 1,218. 

In addition, these lines were further checked by comparing the measured aud computed 
lengths of all sections of the boundary except the Colorado lliver section, the data for the 
computatious being furnished by the astronomical observations at or near the extremities of each 
of these sections. These comparisons are shown in the following table: 



Table showing discripi 



ired and compHted distances along the homidary. 



Section.^. 


Computed 
distance. 


Stadia distance 

reduced to 
mean sea level. 


Discrepancy 
add algebra- 
ically to 
stadia dis- 
tance. 


Discrepancy 
equals 1 in— 




Meters. 
159,193.4 
49, 830. 1 
272,954.2 
372,887.3 
225,570.2 


Meters. 
158,708.4 
49,846.1 
273, 073. 4 
373, 104. C 
225,151.7 


+ 425. 

- 16.0 

— 119.2 
-217.3 
+ 418.5 


375 
3,114 
2,290 
1,710 

539 













TOTALS OF ABOVE DISTANCES FROM INITIAL MONUMENT ON KIO GKANDE. 



Monuments Noa. 1 to 40. . 
Monuments Nos. 1 to 53 . - 
Monuments Nos. 1 to 127 . 
Monuments Nos. 1 to 201. 
Monuments Nos. 1 to 258. 



159,193.4 


158,768.4 


+ 425.0 


209, 023. 5 


208,614.5 


-t 409. 


481,977.7 


481,687.9 


+ 289.8 


854, 865. 


854,792.5 


+ 72.5 


1,080,435.2 


1,079,944.2 


+ 491.0 



In the cases of the first and fifth .sections of the table, the discrepancies betweeu the meas- 
ured and computed distances are doubtless greatly increased by the large local ditt'erences of 
station error which were found to exist both on the liio (hande and the Pacific coast. 

Tills was further indicated by the fact that there were three iudependent measurements of 
the first section by United States corrected chain, by United States stadia, and by Jlexican 
stadia, the extremes of which (liircicd h.s.s tli:in do meler.s, while their mean diflered about six and 
one-half times this am(mut from llir roniiMiiiMi ilisi^inco. 

There were two independent incasmcnicnts of tlie fifth section, by United States stadia and 
by Mexican stadia, which differed by less than 25 meters, while their mean tliffeied more tlian JOO 
meters from the computed distance. 

It will be observed that some of tlie preceding distances differ slightly from tliose given in 
the tables of final distances between monuments. This is due to the fact that remeasurements 
were made of all distances, wherein serious discrepancies were discovered when the United States 
and Mexican distances were compared previous to the erection of monuments, lu order to give a 
true idea of the accuracy of stadia work, the original measurements only, uncorrected by the 
remeasurements, are given in the preceding table, while the results of the remeasurements are 
included in the tables of final distances. 

These results are of interest, as showing the accidental errors in stadia work, wliicli occur in 
spite of all precautions. luasnnu-li as the United States and Mexican measurements were made 



UNITED STATES AND MEXICAN BOUNDARY. 



157 



at different times, were totally iiidepeiKlent of one aiiothei-, and were generally not compared for 
months after tbey were made, it is Mr to assume that the discrepancies shown by these compari- 
sons included the greater number, if not all, of the accidental errors of the stadia measurements. 

Two hundred and flftysix distances, averaging 4,235.7 meters each, were compared, and 
remeasurements were made wherever serious discrepancies were shown. These reuieasurenients 
disclosed three cases in all where it was evident that the United States measurements contained 
accidental errors, either in reading the rod or in recording the readings. Two of the errors were 
about 100 meters each, and were probably due to errors in rod reading; the third was about 30 
meters, and was probably due to a clerical error iu recording. 

As the total number of sights taken in measuring the compared distances was 5,0.59, and as 
it is extremely unlikely that two errors of this character, exactly equal iu amount and with oppo- 
site signs (thus balancing one another), occurred in any single one of the 256 distances, when but 
three were found in all, it miiy be assumed that 3/.505!) gives a fair idea of the probability of an 
accidental error of any considerable magiutude, where the observers are intelligent, careful, con- 
scientious men, keep their own notes, and take foresights and backsights at each station. In 
all, four observers were engaged in measuring distances along the boundary line proper, and three 
of them had one accidental error each. 

In this connection it is interesting to cnmi)are the relative effect of the accidental errors of the 
stadia with those of the chain. 

In a distance of 1.53,841 meters, 7,692 chains of 20 meters each, G chains were either added or 
dropped accidentally, i. e., 1 chain in every 1,282, or an error from this cause of 1/1282. 

The three accidental stadia errors before alluded to aggregated 247.46 meters in a total 
distance of 1,080,435 meters, or an error from this cause of 1/4366. 

The preceding discussion has been entered into in detail because it is believed that seldom, 
if ever before, has it been possible to check in this manner work done on so extensive a scale, 
and thereby to determine, even approximately, the effect of errors the frequency ( f the probable 
recurrence of which is almost wholly unknown. 

Of lines of the second class 1,017 miles were run, of which 118 lines, aggregating 514 miles, were 
closed on points ou the main lines, by the method of latitudes and departures, with an average 
error in distance of 1 in 753. Twenty-five per cent of these lines showed an error in closing 
greater than 1 in 500; 31 per cent showed an error in closing between 1 in 500 and 1 in 1,000; 30 
per cent showed an error in closing between 1 in 1,000 and 1 in 2,000, and 14 per cent showed an 
error in closing less than 1 in 2,000. 

The following table was prepared to show the effect of the seasons ou the accuracy of the work : 



Season. 


Aggregate 

leTgtlfof 

lines. 


Krror in 
dist.anco 
on closing 
Cnalsl 


Meiin error ou closing, per 
kilometer of line run. 


In azimuth. 


In elevation. 


Spring 


Metert. 
138, 702. 83 
298, 147. 87 
152,325.01 
237, 339. 65 


602 

728 

1,090 

742 


, „ 
1 24 

45 

1 01 
1 07 


Meters. 
0.103 
.141 
.101 
.128 






Winter 




826,515.90 


752 


59. G .123 



Topographic field work was commenced in February, 1892, and carried on continuously until 
completed, in October, 1893; and in preparing this table the seasons, for couvenience, were divided 
as follows: 

Spring: March, April, May. 

Summer: June, July, August. 

Autumn : September, October, N'ovember. 

Winter: December, January, February. 

An inspection of this table .shows that the least accurate work w.as done in spring, and the 
mo.st accurate in autumn — a result which was due partly to inexperience on the jiart of the observers 



158 



UNITED STATES AND MEXICAN BOUNDARY. 



during the spring of 1892, but more especially to the effects of work done ou the Yuma Desert in 
March, 1S'J3, under conditions very unfavorable for accuracy. 

The same lines were then grouped with reference to length of courses, in order to determine 
how tlieir accuracy was affected thereby. This grouping is shown in the following table: 



Numbor 
III- lines. 


•iS- 


'^ofH!''' 


Average 
immbei^of 

pri'ne. 


Average 
error in 
distauceon 

equals 1 in— 


Average error on closin", 
per kilometer of lino run. 

In azimuth. In elevation. 


29 

28 
12 
118 


Meters. 
111,823.2 
280.700,8 
290,033.9 
143, 3.12. 


Meters. 
253.0 
350.7 
437.7 
580.4 


1.5.2 
10.1 
23.7 
20. G 


553 
782 
817 
780 


■ " Meters. 
1 r,5 0.160 
1 04 .096 
43 .103 
37 1 .190 


820,515.9 


386.2 18.1 


752 


59.0 .123 



From this table it would seem that there was little or no difference in accuracy in sights 
ranging from 300 to 000 meters in length, while for sights less than 300 meters a much smaller 
degree of accuracy was obtained. Such a conclusion, however, must be greatly modified by the 
fact that very long sights are taken only when all conditions are favorable, while short sights are 
necessary when much wi-nd is blowing or when the air is "boiling," conditions which are both 
unfavorable for accuracy. The shortest average length of course in any closed line was 92.4 
meters, and the greatest average length 704.0 meters. It is not likely, however, that sights as 
long as 500 or 600 meters could be taken advantageously anywhere except in atmosphere as clear 
as that of the Southwest. 

With the idea of determining to what extent the accuracy of the work was increased by 
compensation of errors iu the longer lines, the whole number of lines was divided, with reference 
to the number of courses in each line, into two classes, as shown in the following table: 



Number 
of lines. 


■•IF 

Meiers. 
238, 732. 2 
587, 783. 7 


nti^r^^f 
courses 
per line, 

9.7 
30.9 


Average error in 
length of distance on 
course. closing 

[equals lin- 


Average err 
per kiromete 


or on closing, 
r of line run. 


In azimuth. 


In elevation. 


47 


2[eters. 

348. 683 
404.9 784 


1 28 
47 


Meters. 
0.165 
.107 


118 


820, 515. 9 


18.1 


386.2 752 59.0 


.123 



This table shows that both the azimuth error and the error in elevation were more affected 
by the number of courses per line than was the error iu distance, but that the accuracy of all 
increased with the number of courses per line. 

Finally, to show how the character of the work was affected by practice on the part of the 
observers, the following table was arranged, comparing the lines run in 1892 with those run in 1893 : 



Tear. 




Aggregate 


Average 

length of 

lines. 


Average 
length of 


of courses 
per line. 


Average 

distance on 

closing 
equalslin- 


Average eiTor on closing, 
per kilometer of line run. 


of lines. 


lines. 


In azimuth. 


In elevation. 


1892 


81 
37 
118 


Meters. 
449,773,9 
376, 742, 


Meters. 
5,552,8 
10,182.2 


Meters. 
341.5 
457.8 


16,3 
22.2 


697 
829 


1 18 
35 


Meters. 
0.130 
.116 






826, 515, 9 


7,004.3 


386.2 


18.1 


752 


59.6 .123 



Most of the work during the two years was done by the same observers, with the same 
instruments and rods, and under practically the same general conditions, consequently it is fair 
to assume that all differences in the character of the work during the two years were the direct 



UNITED STATES AND MEXir'AN BOUNDARY. 



159 



result of practice and experionco on the part of the observers. Tlie table shows that both the 
average length of the lines and that of the courses was greatly increased iu 1893, as was also 
the accuracy in distance, aziinutli, and elevation — notably iu azimuth. 

A study of the preceding tables shows that the average azimuth error, on closing, per kilometer 
of line run, varied approximately inversely as the product of the S(iuare root of the average 
number of courses .per line into the average length per course; or, denoting these quantities by 
e, N', and /, respectively, we have v varies as 1 I v/ -N, which is the theoretical law of variation, and 
becomes 1/ v/N when the courses are of enual length. 

Theoretically this last ratio should also be true for the error in distance on closing; but 
in practice this w:is not found to be the case, the variation being nnich more gradual, indicating 
the existence of constant errors, which neutralized, to a considerable extent, the theoretical 
compensation. 

Since the conclusion of the survey it has been shown by Mr. L. S. Smith, C. E., now assistant 
profes.sor of topographical engineering in the University of Wisconsin, but in 1892-93 occupying 
the position of transitman on tliis survey, partly from observations taken during the progress of 
the survey aiul partly from others taken more recently (see Chapter X, Appendix, of the 
present report), that the constant error alluded to is very lai'gely due to the efiects of "differential 
refraction," i. e., the diflference in the amount of refract ion experienced by the upper and lower 
lines of sight, which difference varies with the season and with the hour of the <lay, and affects 
the accuracy of the interval determination, unless this determinatinn is extended over a period 
sufficiently long to embrace the average conditions under whicli the jiroposed work is to be 
prosecuted. 

Of the average error of all lines of the second class, 1/752=1. .53 meters per kilometer, about 
20 per cent, or 0.29 meter, was found to be due to azimuth error, leaving an error of 1.04 meters 
per kilometer = 1 962, as the average error due to the measurement of distance alone. 

The line of levels carried from the liio Grande to the Pacirtc afforded an exceptional oppor- 
tunity for checking the accuracy of the elevations determined by stadia. 

All lines of the second class have been arranged, with respect to their average vertical angles, 
as follows: 



Nnii.ber 
of lini«. 


Aggregate 

leiigtb of 

liBes. 


Sum of verti- 
cal com- 
ponents of 


Average 
vertical 
angle of 


,;;§!?: ;'"'i;-- 


14 


Meters. 
182, 960. 2 
338, 132. 5 
180,426.2 
112.02.5.4 
0, 071. 6 


Meters. 

1,262.4 
11,700.1 
12, 139. 8 
11,930.6 

1, 052. 


24 

1 59 
3 43 
6 05 
8 35 


Meter. 
0.053 
.111 
.150 
.181 
.492 


1 ™ 


118 


826,515.9 




.123 











The angles in the fourth column of the table are obtained by dividing the numbers in the third 
imn by the corresponding ones in the second column, the i-esults being the tangents of these 



On examining this table it is seen that the error in elevation on closing increased very rapidly 
with an increase of the average vertical angle, while the error in distance actually decreased. The 
conditions for obtaining stadia elevations with accuracy in the region along the boundary were 
peculiarly unfavorable, owing to the great and sudden changes of refraction during the hours 
most favorable for field work, and it is therefore reasonable to suppose that with the same 
instruments and methods much greater accuracy would be obtained in a more favorable climate. 

The lesser degree of accuracy, as regards distance, of the lines with small vertical angles is 
probably due largely, if not entirely, to "differential refraction," which is greatest on the flat 
valleys, mesas, and deserts where the lower line of sight passes closest to the surface throughout 
its entire length. 



160 UNITED STATES AND MEXICAN BOUNDARY. 

Including all classes of work. 00,971 sights were taken by tbe transit men, who at each sight 
read and recorded both tbe horizontal and vertical angles. The total time of the transit men was 
ecjuivalent to one man for fifty-four inonths, whicli, excluding only Sundays and national holidays, 
gives an average of 44 sights per day for each transit man during the entire twenty months of 
the survey. In this connection it nuist be remembered that in addition to these sights the 
transit men took sketches covering the entire topographic belt and reduced the greater jiart 
of their notes in the field, and that more than half of the sights were taken in sleep and rugged 
mountains, where much time was unavoidably consumed in getting from stntiou to station and in 
traveling to and from woi-k. 

As an illustration of these delays, an instance mentioned by Mr. J. L. Van Ornum, assistant 
engineer, in charge of the topographical party, will be given: 

A siglit of about 2,000 feet was taUeii from one mountain ridge to tlie next, between whicb tliere was a ravine 
about 1,000 feet in depth. Before 10 o'clock tbe transit man began his descent from tbe ridgo to cross the ravine and 
to climb to tbe point just observed, while he sigu.aled the stadia man to cross from that point a second ravine to a 
third ridge for obtaining an advance sight. Approaching sunset forced then) both to return to camp before they 
coubl reach tlie intended points. 

The average length of the courses of the '• main lines" was 214.3 meters; of the "side lines," 
358.1 meters, and of the side siglits from these lines, 34(i meters. The shorter courses in the main 
lines were necessary iu order to locate profile points on these lines. 

The average distance to the points located, by intersections within the topographic belt, was 
3,000 meters, and to those outside of this belt, 22,000 meters. 

Since during the entire period of the survey the transit men each averaged about 31 locations 
per day, and since tlie average number of locations per square mile within the topographic belt 
was 22, it is evident that the rate of progress for each transit man during the duration of field 
work was 1.4 square miles per day. 

It is seen also tluit had it been necessary to run only meander lines, without side sights, the 
transit men would each have averaged about 8 kilometers ])er day during the entire survey, 
excepting only Sundays and national holidays — a rate of progress which clearly shows the 
superiority of the stadia over the chain when the character of the country is considered, and when 
it is remembered that the stadia method gives both the horizontal and vertical angles, as well as 
the distance. 

LINE OF LEVELS. 

A line of levels, which, with its connections, aggregated 732 miles in length, was carried along 
the boundary from the Rio Grande to the Pacific Ocean, and connected at El Paso and Yuma with 
bench marks of the Southern Pacific Railway, and at San Diego with a bench mark established 
by the United States Coast and Geodetic Survey. To this line were referred all transit elevations, 
the datum plane being that of mean sea level of San Diego Bay. 

Great cai'e was taken in I'unning this line; the rods were held on iron pins driven firmly in 
tlie ground; equal foresights and backsights were taken, and at each setting of the instrument 
both the backsight and foresigjit were read until two values of each were obtained, which did 
not differ more than 0.001 meter, tlie rod having been undamped and reset after each reading. 
The mean of these two values was taken as the true reading. 

In all, 0,663 instrument stations were occupied, each station representing four accepted rod 
readings on "turning points." In addition to these, 4,368 single readings were taken on points 
along the boundary. 

Reducing the Southern Pacific bench marks at Yuma and PIl Paso to mean sea level of San 
Francisco Bay in order to check the line of levels, which is referred to mean sea level of San Diego 
Bay, the discrepancy was found to be — 0.05 meter at Yuma and + 2.62 meters at El Paso, the 
minus sign indicating that the Southern Pacific elevation is the lower of the two, and the plus 
sign that it is the higher. 

Form San Francisco to Yuma the distance by the Southern Pacific Railway is 731 miles, and 
from San Diego, along tlu line of levels, the distance is 160 miles. To El Paso these distances 
are 1,294 and 728 miles, respectively. 



UNITED STATES AND MEXICAN BOUNDARY. 



161 



The "boiling" of the air generally caused leveling to be su.speiuled from about 1() a. m. to 
3 p. ni., thu.s rendering tlie progress of tbis work nece.s.sarily somewhat slow. 

The time occupied in this work was equal to one level man for twenty-five and two-thirds 
months, which, excluding only Sundays and national holidays, gives an average of 14.8 for the 
number of instrument stations occupied per day, and CO for the nnmber of accepted rod readings 
per day for the entire time that the survey lasted. An idea of tlie rough character ctf the country 
can be formed from the fact that the average length of sights for the entire line of levels was but 
(il meters. 

In addition to numerous bench marks left on natural objects, which are fully described in the 
proper notebooks, the following table gives the elevation of the upper surface of the masonry 
base of each monument, together with the oftset from the level line (along which the profile on 
the field maps is plotted) to the monument, thus enabling this line to be easily recovered at any 
time, should it ever become necessary: 



Monnmenta. 


Offset to 


Elevation 
of tup of 

"EH" 

mean sea 


Probable 
error of 
doubtful 
elevations. 


Monuments. 


Otlset to 
Tertct'ed. 


Elevation 
of top of 

base above 


Probable 

doubtful 
elevations. 




Meters. 
1.02 
1.00 
2.00 
3.77 
10.77 
22.04 
38.26 
60.195 
64.31 
89. 525 
122.46 
22. 91 
14.36 
7.305 
4.415 
4.14 
4.14 
4.48 
5.99 
9.35 
14.575 
20.72 


Meters. 
1,131.9 
1,303.8 

i ;:S:: 

1,245.5 
1,250.9 
1, 255. 1 
1,297.2 
1,288.7 
1, 259. 1 
1,248.1 
1,248.1 
1,239.5 
1,236.2 
1,319.3 
1,280.1 
1,280.1 
1,269.7 
1,202.6 
1,205.6 
1, 208. 4 
1,211.0 


Meters. 


21 

t::;::::::;::::: 

24 

25 


Meters. 
27.05 
31.11 
34.53 
45. 645 
56.65 
60.84 
2.44 
2.935 
4.74 
7.90 
12.02 
18. 085 
22.79 
25.20 
34.90 
47.82 
39.37 
69.48 
79. 205 
90.605 
98.97 


MeUrs. 
1,213.1 
1,212.9 
1,219.4 
1,259.3 
1,297.7 
1,315.8 
1.315.8 
1.294.8 
1.306.0 
1,272.6 
1.271.7 
1,433.5 
1,487.8 
1, 387. 6 
1,387.2 
1,346.2 
1,347.2 
1, 384. 7 
1,458.8 
1,518.4 
1,494.2 


Meter,. 


4 












±1.00 






±1.00 
±1.00 
±1.00 


26 

^::::::::;::;:;;; 

29 

30 

31 

:: 




8 

9 








± .50 








±1.00 


12 

13 


± .50 
+ .50 
±.50 




14 




± .50 






15 




36 




±1.00 
± .50 






17 


38 


:=:: 




39 


19 

20 




40 













On parallel 31° 47' the monuments are all north of the tangents, and the oftsets are measured 
in the meridian. 



Monuments. 


Oftset to 
as erected. 


Elevation 
of top of 
masonry 
base above 
mean^sea 


Probable 
error of 
doubtful 
elevations. 


Monuments. 


Offset to 
M°erTted. 


Elevation 
of top of 

base above 

"level^* 


Probable 
error of 
doubtful 
elevations. 




j Meter 


00 

uo 

00 
00 
00 
00 


Meters. 
1,494.2 
1, 509. 1 


3Ieters. 


47 


Meters. 
.02E 
.03E 
.05E 
.07E 
.09E 
.lOE 
.00 


Meters. 
1,294.8 
1,313.9 
1,326.8 
1,335.2 
1,344.1 
1,449.7 
1,408.2 


Meters. 


41 






42 


1,404.2 
1,333.0 
1,279.6 

1,255.7 
1, 270. 8 


49 




43 




50 






51 


1 


45 

























162 UNITEIJ STATES AND MEXICAN liOUNUARY. 

On the meridian section the offsets are perpendicular to the meridian. E = Bast. 



Meters. 

— 6.49 

— .5.87 



b.ase .abovi 
level. 



-118. .'•.!l 
—101. 01 



1, 408. 2 
1,390.0 
1,508.9 



1,543.0 
1,413.5 



1,619.7 
2,048.3 
1, 576. 9 
1,573.1 
1, 573. 1 
1,584.1 



+ 37.51 


1,266.8 


+ 84.84 


1, 322. 


+157.13 


1,211.1 


+209.80 


1,172.4 


+257.32 


1,132.6 


— .73 


1, 132. 6 


— .14 


1,101.7 


+ 4. ,56 


1,243.1 


+ 9.85 


1, 465. 1 


+ 12.62 


1,479.4 


+ 15.80 


1, 374. 2 



Probable 
error of 
doubtful 
elevations. 



56.72 


1,204.2 


79.15 


1,248.6 


31.23 


1,315.8 


30.00 


1,354.1 


27.41 


1,390.3 



Offset to 
.18 erected. 



— 23. 10 



- 7.62 

- 30.76 

- 51. 18 

- 52. 77 

- 59. 67 

- 78. 10 

- 85. 60 

- 94. 15 
-110.33 
-106.00 
-103. 05 

- 87. 18 

- 70. 20 

- 59. 97 

6.20 

- 16.40 

- 42.09 

- 50.82 

- 65.76 
r 85.405 
h 108. 28 
H18.56 
h 66. 67 
I- 42.16 
h 31.45 
h 12.33 

I 6. 08 

- 3.63 

- 12. 70 

- 21.21 

- 24.63 



Elov.ition 
of top of 
masonry 

base .above 



1, 399. 7 
1, 375. 9 
1,354.2 
1,327.1 
1,316.1 
1,316.1 
1, 426. 6 
1,839.9 



1,611.0 
1, 018. 5 
1, 596. 2 
1, 583. 3 
1,.549.4 
1,489.7 
1,485.6 
1,453.1 



.3 |. 



1, 750. 5 
1, 072. 3 



1, 132. 9 
1,248.3 
1, 272. 1 
1, 217. 8 
1,173.9 
1, 248. 7 
1,330.6 
1,381.3 
1, 622. 6 
1,592.05 



UNITKD STATES AND MEXICAN BOUNDARY. 



163 



On parallel 31° 20' the offsets are measured iu the meridian; tliose to the north of the tangent 
are "+," those south of the tangent are "— ". 



— - 


Offset to 


Elevation 
of top of 
masonry 

base above 

™lovel. 


Prnbablo 

dml'lHri'il 
e.evat,„...| 


Moim.nenta. 


Offset to 
mouuinint 
as erectid. 


Elevation 
of top of 

baau above 

mean sea 

level. 


Probable 

iloiiblful 
elevations. 




0.00 

-1.81 

.00 

+ .15 

-1- .05 

1 .03 

H .04 

.00 

.00 

.00 

- .05 

- .03 
.00 

- .10 

- .05 

+ 'Z 

.,- .13 

.00 

- .39 

- .27 

- .28 

- .55 

- .41 
-.29 

- .16 

- .08 
.00 

+ .02 
.00 
+ .29 
+ .20 
+ .07 
+ .01 


Meters. 
1,592.05 

1,011.82 

1, 505. 34 

1,189.91 

1,221.20 

1,240.82 

1,204.63 

1,254.37 

1,370.28 

1,147.74 

1,0.W.51 

1,105.96 

1,228.05 

1,327.74 

926. 06 

832. 65 

783. 63 

801.97 

1,080.42 

817.24 

775.60 

749.49 

720.82 

702.17 

090.56 

804. 72 

542.67 

520.80 

511.75 

507.26 

529.66 

715.05 

515. 84 
745. 18 
702.51 
452.43 
437.30 
421.24 


Meiers. 




Meters. 

.00 

.00 

h .02 

-1 .07 
1 .20 
1 .10 
+ -11 
+ .07 
.00 

- .04 

- .13 

— .11 
-.22 

- .51 

- .43 

— .79 
-.82 

- .56 

- .50 

— .50 

— .31 

— .12 

— .21 
-1- .15 

+ .10 
+ -14 
+ .08 
+ .07 
+ .04 
+ .11 
+ .11 
+ .06 
+ .13 

+ .00 
.00 
.00 


Meters. 
421.05 
565. 27 
395.33 
369.37 
379. 12 
334.00 
308. 20 
313.93 
365. 40 
329. 12 
261.88 
273.76 
251. 84 
210.97 
245.49 
278. 72 
339. 27 
587.75 
614.35 
617.85 
479.68 
319. 16 
547.73 

644.34 
432.57 
242.34 
215.57 
200.93 
' 173. 17 
140.81 
142.11 
81.45 
51.01 
47.90 
48.92 
44.92 
41.42 
20.00 


i:s 








169 




1_9 












171 




m 












173 




lU 


174 








175 

170 








no 








7 




178 




118 








9 








140 










182 




142 








144 




184 












146 




186 








' 








148 












]90 




■" 








151 








153 
















1j5 
















157 




197 












1j9 
























162 
















16^ 












205 


±0.20 


166 








1 



164 



UNITKU STATES AND MEXICAN BUUNllARY. 



On tlie Soaora azimuth line offsets are measured perpendicular to the line as run; those 
measured to the north are marked " + ", those measured to the south are marked " — ." 



ileters. 
— 0.39 



+ 6.04 
+ 8. 37 
I 10.72 
I 12.62 
I U.4A 



23.29 
17.85 
11.12 
9.18 



. 18. 53 
■ 25. SO 
• 18.20 



Elevation 
of top of 
maaonry 
base above 



52. 70 
45. 23 
41.47 



22.48 
15.77 
8.74 
5.09 



83.54 
114.03 
64.17 



+ 2.68 
+ 8. 16 
-Y 14.60 
+ 18.99 
+ 25.38 
)- 30.14 
H- 32.92 
+ 40.33 
+ 48.00 
+ 50.50 
+ 56.10 
+ 60.79 
+ 62.14 
+ 50.47 
+ 40.41 
+ 31.78 
+ 11.94 



baae abovt 
mean aea 



Meters. 

900. 49 

1,063.05 

1, 151. 83 

1,121.13 

1,071.13 

1, 090. 70 

961.21 

922. 34 

922.86 

785.97 

635. 33 

571. 20 

579.51 

1,041.55 

1,057.46 

328. 28 

249. 14 

323. 12 

517.85 

161. 19 

150.21 

147. 88 

34.68 

137.41 

119.47 

•18.56 



* Top of granite base. 

On the California azimuth line offsets are measured perpendicular to the line as run; those to 
the north are marked "+", and those to the south are marked " — "'. 

Elevations helow mean sea level are marked '' — ". 

The flgures in the second column give the offsets from the line actually run, and along which 
the profiles were taken, to the center of the monuments as erected. Offsets are in meters. 

Those in the third colunui give the elevation (in meters) of the top surface of the masonry- 
base of the monuments, referred to mean sea level of San Diego Bay, California. 

Elevations unmarked by their i)robable errors in the next column are believed to be (correct, 
with respect to the line of levels, to within less than 0.10 meter. 

Ou parallels 31° 47' and 31° 20' it will be observed that the elevation is in many cases given 
as having a large probable error, 'rhis is due to the fact that the line of levels was run several 
months in advance of the erection of the monuments, and that on those parallels the ek^vations 
were not transferred to the monuments when the latter were erected, but afterwards in the oftice 
by the aid of photographs of each monument and the surface in its vicinity, elevations at or near 
the site of the monument, and such other notes as were available. 

Whenever, owing to the distance of the nearest station of known elevation, the lack of neces- 
sary details in the photographs, or from any other cause, the elevation could not be transferred 
within 1 decimeter, the degree of approximation which it was believed could be safely relied 
upon is given as the probable error of the elevation in question. 

The distances between the monuments in the preceding table are given on pages 34 and 35 
of the Keport of the Joint Commission. 



UNITED STATES AND MEXICAN BOUNDARY. 165 

MAGNETIC DECLINATION. 

The known azimuths of the tangents and of the different sections of the boundary line 
fiiruished an easy method of determining, by means of the transit compass, the magnetic declina- 
tion at various points along the boundary. In all, 534 compass readings were taken, at an average 
distance apart of 1.26 miles. The index error of the compass was determined and the readings 
checked by comparison with a full set of magnetic observations made in 1892 at San Diego, Cal.; 
Yuma, Ariz.; Nogales, Ariz., and El Paso, Tex., by the United States Coast and Geodetic Survey 
party which determined the latitude and longitude of those points, and also by comparisons with 
observations made with a magnetic theodolite by Mr. J. F. Hay ford, assistant astronomer, at the 
12 astronomical stations between the Kio Grande and the one hundred and eleventh meridian. 

The period covered by the observations was from March 31, 1892, to October 16, 1893. Tlie 
corrected observations have all been plotted, but owing to the uncertainty regarding the secular 
variation along the boundary no attempt to reduce them to any fixed epoch was made. Owing to 
this fact, and to the difBcnlty of reading the ordinary compass needle accurately, the curve of 
magnetic variations may at some points be several minutes in error, and is interesting principally 
as showing the distribution of magnetic declination and its local variations. , 

An examination of this curve shows tliat great local changes in declination invariably 
occurred when the line crossed over a lava-covered region, and that in one case this variation 
underwent a range of .5° 50' in about 5 miles. In all, there were ten localities along the boundary 
where the declination underwent a change of from 1° 40' to 5^ 50' in the course of a few miles. 
Four of these places were in lava-covered regions and six in mountains. 

In no cases except in volcanic regions were large local variations of declination found on the 
deserts or in the valleys. 

In order to judge fairly of the value of the stadia in topographical work, it is necessary to 
know the conditions under which stadia work was prosecuted on this survey. 

The conditions favoring this work were the wonderful clearness of the atmosphere, the general 
absence of trees and thick undergrowth, the remarkable liealthfulness of tlie region, its delightful 
winter climate, and the very few rainy days. 

The unfavorable conditions were the intense heat on the deserts in summer, and the total 
absence of shade there; the scarcity and poor quality of the drinking water; the inability to 
procure fresh meat on the deserts, where most needed; the long haul for pro\ isions, forage, and 
water; tlie violent sandstorms on tlie Colorado Desert, and the great atmosplieric uiisica<lincss. 

As to the temperature, it will l)e sufticient to state that on the deserts in summer the thcr 
mometer at times attained a maximum of 118° F. in the shade. Tliis gives but little idea, 
however, of the temperature in which work was prosecuted; for t)f available shade for the working 
parties, even during the long noon intermission, there was absolutely none, and it was to sunshine 
temperature alone that they were exposed throughout the entire day. This temperature, during 
the month of June, 1893, generally varied from 130'^ to 140° F. at 8 to 9 a. m., Uo'^ to 160o I'\ at 1 to 
2 p. m., and fell below 130° F. at it to 7 p. m. In spite of this intense heat, work was vigorously 
prosecuted every day, and the general liealth of the party was excellent, owing, doubtless, to the 
fact that the extreme dryness of tlie iitniosphere teiiiiiered the effect of the heat and caused rajiid 
radiation, due to which the nights were in general coid and pleasant, however intense was the heat 
during the day. 

While, owing to the causes above mentioned, such exti-eiiie heat is less deliilitating than is 
the case where more luoislurc exists in the atmosplinc, yet I lie bodily discomfort therefrom during 

the middle of the day is by i icans so small as it is poimla l,\ suiiposcd to be, and few who have 

once worked in such tciiipeiatiiics would care to reix-at rli(^ (■xpcriciice. 

The greatest obstacles to accuracy in the statlia .measurements were, however, atmospheric 
unsteadiness and winds. 

Under the term "atmospheric unsteadiness"' are included certain peculiarities of atmospheric 
action — "difl'erential refraction," refraction, and "boiling." The first has already been alluded 
to. The second is well known, but it should be stated that the daily variations in the amount of 
refraction and the suddenness of these variations are exceptionally great in this region. 



166 UNITED STATES AND MEXICAN BOUNDARY. 

The " vibration" or "boiling" of tlie atmosphere is familiar to everyone who has been engaged 
iu field work, but occurs to a remarkable extent in the arid regions of the southwest, and was a 
subject of study on this survey by Mr. John F. Hayford, assistant astronomer, Messrs. J. L. Van 
Ornum and E. L. Ingram, assistant engineers, and Mr. L. S. Smith, transit man, from whose notes 
and reports the following facts were obtained: 

The number of vibrations during consecutive minutes was very variable, being iu some cases 
three times as great as in others, the most rapid vibrations occurring in the intervals when the 
breeze ceased. 

When a steady breeze was blowing objects whose form was distorted and irregular from the 
atmospheric vibration.s always suft'ered more distortion on the leeward than on the windward side, 
and their outline appeared actually to be blown with the wind like the flame of a candle. 

The lateral component of the vibration was in general of less amplitude tlian tlie vertical 
component, and gave to the rod a sinuous appearance and a wave-like movement, always from the 
bottom toward the top. It was also observed that this comijonent of the vibration was always 
greater at the bottom than at the top of the rod. 

The lateral component of the vibratiou aflects the accuracy of stadia work, as regards 
azimuth, to a greater extent than us regards distance. 

The vertical component of the vibratiou was of a compound character, consisting of a primary 
vibration, upon which was sui)eriui])0sed a secondary vibration, more rapid but of smaller 
amplitude. 

Atmospheric vibration was found to increase rapidly with length of sight; with ditierence of 
temperature between the air and earth; with the brightness of the sun, and with the absence of 
vegetation. 

While the general effect of this vibration is to decrease the accuracy of a single sight, yet 
errors due to this cause alone are probably compensatory, balaucing one another on an extended 
survey. 

So far as atmospheric vibration alone was concerned, it was the general rule throughout the 
survey to continue work whenever the amplitude of the vertical com])onent of this vibration 
appeared less than 1 centimeter at a distance of 200 meters, at which distance this vibration often 
reached li and sometimes even 2 centimeters. 

When wind alone was the disturbing element, work was (continued as long as the stadia men 
were able to hold the rod up against it. 

That stadia work was prosecuted under the adverse coiiditions mentioned in the two preceding 
paragraphs was not because it was supposed tliat accurate work could be done at sucli times, but 
because the great difficulty and expense of procuring water and supplies rendered it imperative 
that the work should proceed as rapidly as possible, even at a sacrifice in accuracy. 

REPORT OF MR. .1. L. VAN ORNUM, ASSISTANT ENGINEER. 

San Diego, Cal., Ajyril (1, 1894. 

As directed, at VA Paso, Tex., I organized in February, l.sy2, the topographical party of the 
International Uoundary Survey, to consist of two transitmen, each having three stadiamen, and 
one levelman, having two rodinen. This engineering force, with the necessarj^ cooks, teamsters, 
packers, and laborers, formeil the regular topographical camp in its work under my charge from 
the Eio Grande to the Colorado lliver. 

At Yuma, in January, ISO^i, in accordance with the plan for two field parties for the survey of 
the deserts, one of the transitmen and the levelman were ditaclied for tojjographical work on the 
California jiortion of the boundary. Filling their places, I proceeded with the survey to the east- 
ward of the Colorado River and completed the field work in October, 180,'i. 

The transits used were of the usual description, mannl'actured by F. E. Brandis, Sons & 
Co., of New York City, having G-inch horizontal circles reading to 20", vertical circles reading 
to 1' and lO.J-iuch telescopes magnifying 20 diamefers. 

One of the levels used was made by W. & L. E. Gurley, of Troy, N. Y^., and the other by 
F. E. ISrandis, Sons & Co., of New Y''ork City. They were of the usual style manufactured 
by these firms, having ISinch telescopes magnifying about 30 diameters. 



2 

1 

I 

9 

? 

7 




■ 



rig. 2 Target used 
£or yrveasuririg -yibrratioTV. 



Fig-.l. J)esi<^rt. of Stadia^ 



UNITED STATES AND MEXICAN BOUNDARY. 167 

The level rods were the regular New York form of rod, with metric divisions. Gurley's rod 
levels were used for securiug a vertical position of the rod. 

The stadia rods were desigued by us. They were IJ meters long, 1 decimeter wide, 20 
millimeters thick at the middle and tapering to lo millimeters thickness at the ends. Tlie foot of 
each rod was shod with band iron. The face of the rod was divided into decimeteis and centi- 
meters, as shown: 

nTiele. I I 



As distinctive features of this rod will be noted the diamond form of dciiniftt r (li\ ision; 
their entire coloring- on one side of the face of the rod for long distance readin--, whilr at the 
other side they are divided into centimeters for short distance readings; the ml cciitiineter 
divisions to distinguish every half-meter, and the red figure and diamonds, and the changing of 
the centimeter divisio/is to the opposite side of the face of the rod, to aid in distinguishing the 
meters. 

This form of marking was adoi)ted because of its simplicity, while at the same time it 
furnished thedistinctive characteristics given to aid in readily reading the intervals. The twenty 
months of held service confirmed the expectation of their efficiency. Under fairly favorable 
conditions the centimeter divisions could be distinguished at a distance of 1.'50 meters, and spaced 
by the eye of the observer into millimeter readings, while for secondary sights the decimeter 
divisions could be observed at a distance of GOO or 700 meters, and spaced in the sami; way into 
centimeters. While these long and accurate readings indicate the efficiency of the form of rod 
used, the clearness of the atmos[)here also aided in securing this result. 

For reconnoissances, and for aiding my work of sketching and planning operations, I at times 
made use of a i)rismatic azimuth compass and a Locke's hand level. 

The essential work of the topographical party consisted in the measurement of the line; the 
securing of elevations of salient points upon it, and the detailed topograjjliy of a zone i kilometers 
(2i miles) wide on the American side of the boundary. For obtaining these elevations a wye-level 
was used. For the measurement of the boundary within the limit of error desired the stadia 
furnished the best method, ami the transit offered the lightest, most adaptable, and best 
instrument. 

For topography the natural features and {-onditions of the country t(i be traversed led to the 
selectiini of the transit as the l)cst fiekl equipment. The fre([uent remoteness from supplies and 
water, and the great heat of summer, and other hardships to be encountered in an almost unin- 
habited region, necessitated as small a field ])arty as practicable, and suggested the plotting of the 
notes away from the field. The topography, embracing a belt of country 1 kilometers in width, 
required a general onward movement, and a concentration of the work of all instrumentinen and 
instruments on topography as mountain ranges were encountered, all working to advantage in 
limited areas. The occasional lemoteness of work from available camps, and excessively rugged 
character of some of the mountain ranges, called for the lightest eqliipment possible; while the 
necessity of utilizing even tl>e frequent very windy days, and the precipitous mountains often 
requiring vertical angles as high as 00'^ and incclndinu tlic possibility of resections, confirmed the 
selection of the transit as the only practicable instrument for this work. 

The level line, as a rule, followed the tangent lines of the boundary, taking elevations to 
secure a ])rofile and to furnish reference points for elevations in topographical work. When 
difficult mountains were encountered the level line went around and joined the tangent again on 
the further side, a transit profile being taken over the mountain. 

The level party was generally the first to quit work on account of the midday beat. The 
great heat and vibration of the atmosphere necessitated a cessation of work during tlic summer 
months from 10 a. m. to 3 p. m., and often longer. 

Great care was taken to secure as accurate work as possible. Sights were ordinarily limited 
to 100 meters and were restricted to 250 meters. They averaged about (50 meters. The level 



168 UNITED STATES AND MEXICAN BOUNDARY. 

adjustments were tested daily, aud all possible care was taken to protect the bubble tube from 
the disturbiug effects of the heat. Two indepeudent readings were taken on each backsight 
and foresight; if these did not check within 1 millimeter, more settings of the target were made 
until such agreement was secured, the mean of the two being taken as correct. The levelman 
was required to check the final leading of the target on each sight. Each rodman kept a peg 
book for checking the levelman's computations. Each day's work was checked by a summation of 
backsights and foresights by both levelman and rodiiien. 

The level line as carried along the boundary gives the elevation at El Paso 2.67 meters less 
than the elevation assumed at starting. The assumed elevation was the mean of elevations given 
by the Southern Pacific Railway and the Atchison, Topeka and Santa Fe Railway, the former 
having been brought from San Francisco and the latter from St. Louis. 

Further details of the level work are given in the Report of the Commissioners under the 
head of topography. 

The measurement of the boundary line furnished monument distances, distances for the 
profile of the line, and points for the starting and closing of topographical lines. It was made 
by stadia for the whole distance. The length of sights varied from 100 to 300 meters, and 
averaged 214 meters. As a rule the length of sight was smallest toward midday, the vibration 
of the atmosphere already mentioned troubling during the summer for eight or nine hours of 
the day when on the plains, and stopping the work for four or five hours. 

This vibration was the greatest on sandy plains having little vegetation. Though very 
aggravating, it was not so excessive as the temperature and character of the country would 
lead one to expect. The slight humidity of the atmosphere probably modified its amount. 

Work would generaly stop when the amplitude of vibration reached 1 centimeter at a dis- 
tance of 200 meters, while at midday this amplitude would often be as much as IJ centimeters, 
and at times 2 centimeters at the distance mentioned. A peculiarity of the vibration of the air 
was its double character, or what might be called a primary and a secondary vibration. When 
this primary vibration had an amplitude of 1 centimeters and a rate of 30 per minute, at the 
same time would be remarked the secondary vibration, having an amplitude of 2 centimeters and 
a rate of 60 per minute. 

A double measurement of eacli distance was made, first as a foresight and then as a back- 
sight. Besides the profiles over mountains, profile points were often taken, in ravines or on 
ridges, by distance and vertical angle to assist the levelman. This measurement of the line used 
two of the rodmen. The third was occupied in giving topographical points for 200 meters on the 
Mexican side and adjacent points on the American side that could be taken to advantage. 

Incidental to this work there were also taken from the tangent slope angles on the plains 
observations for magnetic declination at intervals of about 2 kilometers (for resume of which see 
Report of the Commissioners under the head of topography), and intersections to and vertical 
angles on mountain peaks and ranges on each side of the zone of instrumental topography. 

Great care was taken to secure a true and accurate interval factor. At first frequent 
determinations were made, and afterwards at intervals, to make sure that there had occurred no 
change of magnitude due to accident or to lapse of time. One determination was made after the 
transit had been exposed to the heat of the day to see if this appeared to aft'ect its interval, 
but no difference was apparent. 

The method usually followed in testing the interval was for two observers to take two read- 
ings, each at intervals of 40 meters, on a ciirefully measured base line (corrected for inclination 
and for the temperature of the tape) 400 meters in length. The transit was placed at a distance 
beyond the end of the base line equal to its focal distance plus the distance from center of instru- 
ment to the objective (f + c). Occasional obvious errors of reading were rejected, and the interval 
factor was determined for each distance. Tlie mean of these was taken as the true factor, giving 
those of the observer who ordinarily used the transit double weight. After the first group of 
observations, when the newly determined factor differed but little from the previous ones (as was 
usually the case), the mean of the latter was given double the weight of the one just taken in 
obtaining the working factor. In all the determinations of the interval factor, made for the transit 
used in the measurement of the line, nearly 800 readings were taken, and the greatest deviation 
of any determination from the mean, during its twenty months of service, was less than 11000. 



UNITED STATES AND MEXICAN BOUNDARY. 169 

Tables of distauces were made for the successive working interval factors in which the term 
/+ c entered, giving an easy and quick way of reducing the stadia reading to distance. 

As before stated, the belt of topography taken was 4 kilometers wide ou the American side of 
the line. The plan of work contemplated the instrninental location and determination of elevation 
of all topographical features that would appear ou maps drawn on a scale of 1/30000, with contours 
at vertical intervals of -0 meters. 

The tangeut lines iu their measured distances aud established elevations were taken as tlie 
basis of the topography. From them stadia lines were run in a general northward direction, from 
the stations of which secondary sights (giving azimuth, distance, and vertical angle) were taken 
on salient points of the terrene, and, covering in this way an advantageous area, the main line 
turned southward, closing again ou the tangent line. 

Each main line was a true transit line, each station being occupied by the transit. The zero 
of the vernier was kept always north, aud two sights for distance aud elevation were taken ou each 
course. To properly cover the terrene, spur lines were often run out from the main line, and where 
there was no indication of magnetic disturbance these spur lines were compass lines. 

Special topographic books were ordered, to contain the reduced held notes as well as the 
original entries. The latter consisted of the stations, azimuths, and stadia readings, vertical 
angles and heights of instrument (above the station), with explanatory notes, and with sketches 
showing the couliguration of the terrene, with the position of stations taken, and the location of 
all water, wood, grass, roads, trails, ranches, and towns. 

Often when crossing a plain with the tangent, transit, and level line, the second transit man 
would form a detached camp with his men in the mountain range ahead or in the one just left, 
while in wide areas of mountains all the instrument men would work on to]K)graphy to obviate too 
great a separation of camps. The vibration of the air interfering with observations much less in 
the mountains than on the plains, a greater accuracy and less interference with the hours of wofk 
were possible. It should be stated that the degree of accuracy of the work was reduced by the 
necessity of constant progress unless absolutely prevented by hard storms. It was the rule that 
field work should continue in storms as long as it was possible for the stadia men to hold up their 
rods in the wind. 

The notes were reduced in the field, and then sent to the oflBce for plotting. The reductions 
were made partly by a computer in the party and partly by the engineers on stormy days, during 
the midday cessation of instrument work, and evenings. Stadia readings were reduced to dis- 
tances and these to horizontal and vertical components, elevations of instrument and elevations of 
all stations were obtained, and the latitudes and departures of all closed lines with the circuit of 
elevatious were computed. The maximum allowable error of closing in distance was 1/300, aud iu 
elevation 1 decimeter per kilometer per degree of vertical angle; distances and elevations on 
the tangent lines were assumed correct in these computations. 

For computing the elevation of stations on closed lines a formula was devised which, by 
taking advantage of the two readings on each course, eliminated the correction for curvature and 
refraction. The derivation of the formula is as follows: 

Let the elevation of Station A (already known) be e, the H. I. there be a, and the vertical 
component of the reading on the next station be m. Let the elevation of this next station, B (to 
be determined), be x, its H. I. then be 6, and the vertical component of the reading back to 
Station A be n. Represent the correction for curvature and refraction by c; m aud n are positive 
or negative quantities according as B is higher or lower than A. 

The following equations, then, are derived: 

1. x=e+aJt-m-\-c (by F. S. from A); 

2. .v=e-\-n—c—h (by B. S. from B); whence: 

3. 2x=2e-\-in-{-n-\-a—h (by adding 1 and '^)■, or: 

4. .r=e + J (rt+)H + ji — 6). 

Equation 4 gives the formula as used, fi'om which the term e has disappeared. Errors due to 

the instrument being in not perfect adjustment, or to heat aflectiug tiie bubble tube or other 

portions of the transit (which is often (juite troublesome), being both errors of a character similar 

to that due to curvature in their mathematical effects, are likewise eliminated. Conseijuently the 

S. Doc. 247 15 



170 UNITED STATES AND MEXICAN BOUNDARY. 

only errors entering the result are those of observation, and nonvertical rod, and sudden changes 
in refraction, which the use of this formula reduces by half; or, if large, such errors are detected 
m the process of reduction, and the erroneous sight is corrected in the held by another observation 
on the course in questioa. The average error of closing before the adoption of the formula was 
more than half greater than after its use. 

After completing the computation of the elevations of the stations ou the closed line in this 
way the discrepancy in elevations on closiug ou the tangent was distributed uniformly backward 
along the line. Errors in closing of latitude and departure were also uniformly distributed. 

The roads and trails of the country which this expedition followed were, outside of the zone 
of topography, and occasional short distances iuside the zone, located by taking the azimuth of 
successive courses with a prismatic compass, and the distances by counting a horse's steps of 
known interval, both the initial and final points of the meander being iustrumentally located. 

In the Dog Spring, Guadalupe, and Perilla mountains the greater part of the topography was 
taken by intersections instead of by stadia. This method was used because it shortened the time 
of field work, and it was made practicable by the occurrence in these places of a few peaks 
commanding the whole region taken. Stations on these peaks were located by intersection from 
the tangent line and from each other, and at these stations transitmen had their positions. 

An engineer with a flagman (both mounted whenever possible) would traverse an advantageous 
area, the flagman signaling at each salient point of the terrene, while the engineer made a contour 
sketch of the region, giving the located points, with their designating numbers, and recording the 
time of each signal. At the same time two transitmen occupied two advantageous positions ou 
commanding peaks, and upon each signal from the flagman took simultaneous observations upon 
his vertical flag, recording the azimuth, vertical angle, and time of each observation. At the close 
of each day's work each recorded observation of each transitman was numbered to cori-espond to 
the engineer's record, the time entry serving as a check in numbering. 

In the office each located point was plotted from the transitmen's stations according to 
the field record, and the distance from each station to each point was measured. From this 
distance and the corresponding vertical angle recorded the vertical component was computed; 
this, when corrected for curvature and refraction, was applied to the known elevation of the 
station, whence was derived the elevation of the located point. There being two observations on 
each point, comparison could be made. Eighty per cent of the points so located checked within 
less than 3 meters, even when the sights were 10 or 12 kilometers long. Of those not agreeing, 
the true elevation was indicated by reference to the contoured sketch. 

It was the intention in such intersection work to use aneroid barometers for securing eleva- 
tions if it was found that satisfactory results could be obtained. With this in view, one Cassella 
and two Queen & Co.'s compensated barometers were read ou the intersection work in the 
Dog Mountains just described. One of them was placed at a transit station and ten-minute 
readings taken to show the atmospheric fluctuations during the day; the other two were carried 
by the engineer and read at each toiiographical point. Tiie barometers were compared both 
before and after the work, and these readings also were recorded. The readings of each of the 
two observed barometers, as modified by these compared readings, were considered with reference 
to the readings of the stationary barometer; and the resulting differences (reduced by Guyot's 
Laplace's formula, as given by Williamson, to meters) gave the barometric differences of elevation. 
From these, knowing the elevation of the stationary barometer, the barometric elevations of the 
topographical points were determined. 

All care was taken to obtain, if possible, satisfactory results; yet the two observed barome- 
ters at times differed from each other at the same station as much as 20 meters, and both differed 
often from the iustrumentally determined elevations to a fatal degree, which at times amounted 
to 40 meters. 

From the Colorado Eiver eastward along the boundary for a distance of 300 kilometers the 
country is quite inaccessible, is almost uninhabited (having one ranch within 30 kilometers of 
the line on the American side), and is a true desert, having but five watering places, and some 
of these of limited capacity. This being such a wilderness, and offering many obstacles to the 
usual rate of progress, it was determined to modify the plans so as to further expedite field work. 



UNITED STATES AND MEXICAN BOUNDARY. 



171 



The method followed in the field work was the same as on previous work in all particulars, 
except for the surface irregularities of the outer 3 kilometers of the topographical belt. In this 
area flags were placed ou all tlie prominent peaks and ridges, and the location and elevation of 
these points were taken by the transit man from the boundary line. The second transit mau 
occupied the positions of these flags, and took azimuths and vertical angles on all flags in sight, 
thus covering the terrene with a network of location angles. At the same time he located other 
important topographical points by resection, where possible, but more often by stadia, and made 
a contour sketch showing the details of the whole terrene, the located flags furnishing the accurate 
groundwork for the whole. 

This method of field work suggests that followed in the mapping. The numerous flag 
locations furnished the salient points, the resections and stadia locations gave other accurately 
determined locations and elevations, and the minor details were tilled in from the field sketches. 

The results proved the wisdom of the plan. Less expeditious advancement would fre(]uently 
have caused serious complications. At one time a threatened failure of water was only averted 
by an arduous and successful search for natural tanks in the Cerro Cabeza Prieta, and by good 
fortune in developing the supply of the Tule Wells. As it was, the survey was enabled to 
successfully cross the deserts and secure its topography in as great detail as the character of 
the county warrants. 

The following table gives a general statement of the topographical work on this survey from 
the Rio Grande to the Pacific Ocean : 



Section. 












Detached lines. 




Transit. 


Compass. 


Number 
sights. 


Distance 
measured. 


tjn^r 


lines. 


Num- 
ber 


^Ce 


linitr 

courses. 


Num. 
li^nfa. 


Num- 
ber 
courses. 


Length 
lints. 


courses. 


Rio Grande to ouc hundred 
and eleventh meridian. . . 

One hundred and eleventh 
meridian to Colorado 


2,388 

1,882 
798 


481, 963 

377,426 
226,467 


201. 83 

200.55 
283.79 


133 

104 

29 


714 

487 
137 


210, 499 

134, 316 
64,200 


295 

276 
469 


51 


523 
399 


181,537 

141, 233 
78, 759 


347 

354 
461 


Colorado River to Pacific 


Total 




5,068 


1,085,856 


214.26 


266 


1,338 


409,015 


306 


91 1 1,093 


401, 529 


367 




Section. 


Cloaefl lines. 


Sights other than turning points. | 


Stadia. 


Topographical inter- 
section. 


Mountain intersec- 
tion. 1 


Nnra- 

b.-r 
lines. 


Num- 
ber 


Length 


Average 
length 


Number of 
sights. 


tjn^^r 


Points 
located. 


age length. 


Points 
located. 


Approxi- 
age length. 


Rio Grande to one hundred 
and eleventh meridi.nn 










13,810 

8,743 
4,500 


333 

346 
386 


1,294 
1,190 


3,200 

2,800 
1,600 


1,170 

1,200 
415 


16, 000 

25,000 
30,000 


One hundred and eleventh 
Tueridian to Colorado 










Colorado to Pacific Ocean 










Total 










118 
























' 




















' 






' 




' 




1 



SUMMATION. 



Kind of location. 


Number. 


terjr 


Total length. 


Stadia sights 


36,692 
2,523 

2,785 


329 
3,000 
22, 000 


12,083,254 


Topographical intersections 






Total 




42, 000 













172 UNITED 8TATES AND MEXICAN BOUNDARY. 

On the closed lines the average error of azimuth per course is 23". The average error in the 
closing by latitudes and departures is 1/752. A further discussion of tlic results obtained is found 
in the Report of the Commissioners under the head of topography. 

Concerning the elevations on closed lines it is to be noted tliat the sum total of the vertical 
components on the aggregate length of lines of 820,516 meters is 38,091 meters, giving as the 
average vertical angle 2° 38' 10". The average error in closing in elevation is 1/374 of the vertical 
component, or 0.123 meters per kilometer of distance. 

By grouping the lines according to their average vertical angle and plotting the corresponding 
errors in elevation of closing (expressed in meters per kilometer) I was enabled to draw tlie mean 
curve. If 6 represents the average vertical anele expressed in degrees, the equation of this 

curve is 3Q(^^;^;-^) + ^ 

Theoretically the error should vary as the tangent of the angle only. The presence of S itself 
in the equation is due, I believe, to the fact that in practice rodnien will not hold the stadia rod 
vertical even with the aid of a plumb line, the tendency being to hold it perpendicular to the 
general slope, and so introducing an error varying with the inclination of the line of sight to the 
horizontal. 

More favorable conditions in the field would change the constants of the equation and give a 
smaller probable error of elevation. These conditions would be secured by not working in very 
windy weather nor when the heat vibrations of the air are troublesome; by using transits whose 
vertical circles will read to a fraction of minute and whose stadia wires are as fine as possible and 
yet plainly visible. 

A reconnoissance from Yuma eastward along the boundary, in February, 1893, developed the 
fact that eastward from old Monument No. II (204), near the Colorado River, there was no authentic 
mark on the line until old Monument No. VI (175), about 103 kilometers distant, was reached. As 
both these monuments are on plains, with three ranges of mountains between, it became neces- 
sary, before the survey could begin from the west, to establish a point on tlie westernmost range 
(the Tinajas Mountains) on a line connecting the two monuments Just mentioned. 

Preparation was made at Yuma for this expedition, which proved to be the most severe on 
the survey. Nearly half of the men deserted, when opportunity offered, on account of the arduous 
duties and forbidding prospect, and i)raise is due the engineers and those of the rodmeu and 
teamsters who helped me to acconiiilisli the purpose of the expedition and continued with the work. 

All my party except one hcliolropeiium at Monument No. II (204) left Yuma by wagon train, 
following the Gila River eastward for 50 kilometers, then turning southward along the east foot 
of the Gila Range. The fii'st water was reached at Tinajas Altas, 00 kilometers from the river. 
Seven kilometers southeast of this jdace two engineers with rodmen were left to occupy with their 
instruments stations on the Tinajas and Lechuguilla Mountains. With the wagon train I continued 
eastward 33 kilometers across the Lechuguilla Desert to the next water, at Tule Wells in the 
Tule Mountains, the easternmost of the three ranges. From this place I sent ahead by pack train 
a heliotropeman across the Tule Desert (73 kilometers) to the next water, at Agua Dulce, about 7 
kilometers from Monument VI (175). 

The plan followed for establishing this line was for the heliotropeman at Monument II (204) 
to show a constant light westward along the line, the engineers to work to the line by successive 
approximations. Fortunately the middle range (the Lechuguilla Mountains) proved to be so low 
at the line that observers could see over it, and the Tule and Tinajas Mountains were the only 
ranges it was necessary to occupy. 

As an initiative I assumed a point on the Tule Mountains as near the line as I could guess, 
and from it showed a heliotrope to the Tinajas Mouutalns. There the engineer, by successive 
trials with his transit, lined in between my light and that at Monument No. II (204). Then he showed 
his heliotroi»e toward me and 1 lined in between him and Monument No. VI (175). By repeating 
this operation the line was continually approached. 

The particular difficulty of the work will be realized when the character of the mountains in 
which these successive approximations were made is known. The Tinajas Mountains are a range 
excessively rugged and precipitous, about 4 kilometers wide, from 300 to 400 meters in elevation 
above the desert, and composed of numerous i)arallel ridges that had to be scaled in succession. 






Old MoNi ment No I, on 



MENTO No. I, EX EL PaciEICO. 



UMTED STATES AND MEXICAN BOUNDARY. 173 

The Tule Mountains are of much the same character, except that they are composed more of a 
succession of peaks than of ridges and are about 12 kilometers wide. Added to this there were 
numerous windstorms raising a dust that often obscured the heliotropes at the distance of about 
70 kilometers, and clouds and thunderstorms farther complicated operations. 

The rodmen detailed to assist me in this work gave out after two or three days, leaviug the 
engineers alone to make the observations and effect all the details of the work unaided. By 
unremitting effort and labor the purpose was finally accomplished, the successive camps called 
in, and the party returned to Yuma. 

When on the regular survey this line was carried tlirongli with a Fauth theodolite and 
reduction made to the true line, it was found that the point set in the Tinajas Mouutaius was less 
than a meter (0.87) from the true line connecting the two monuments. 

My tirst duty is last accomplished. With pleasure I commend the work of Mr. Li S. Smith, of 
Wisconsin, Mr. r. D. Cunningham, of Tennessee, Mr. James Page, of Maryland, and Mr. A. F. 
Woolley, jr., of Georgia, transitmeu, and of Mr. P. D. Cunningham, of Tennessee, Mr. S. W. 
Speiermann, of Utah Territory, and Mr. Ernst Franke, of Colorado, levelmen. The courage, 
efficiency, and faithfulness of these engineers on the topographical work of this survey deserve 
especial mention. 

CHAPTER ^ I. 

OLD MONUMENTS. 

Under the treaties of 1848 and 1853 the boundary was marked by monuments of stone and 
iron. In the process of their erection the line was divided into three sections, the monuments 
being numbered in each section independently. The numbers appeared only on the maps and 
were never placed on the monuments themselves. The first section comprised the Southern 
California boundary, extending from the Pacific Ocean to the Colorado River, a distance of about 
141 miles, and was marked l)y 6 monuments. The second section was the azimuth line from the 
Colorado River to the one hundred and eleventh meridian — 234.3 miles — with 19 monuments. The 
third section was the line from the Rio Grande to the one hundred and eleventh meridian, and 
includes the boundary along parallel 31° 47', the meridian, and the; parallel of 31° 20'. This 
section was marked with 27 monuments according to the maps of the American Commissioner, 
and 28 as shown on those of the Mexican. 

In detail these old monuments were as follows: 

Beginning at the initial point of the survey, at the Pacific Ocean, the first monument was 
located near the coast and, in accordance with the treaty, one marine league south of San Diego 
Bay. This was an elaborate structure of marble, made in New York and brought to this coast by 
a naval vessel, landed in the bay, and hauled on wagons to its destination. It consisted of a 
pedestal and shaft of white marble, the whole 10 feet high, and resting on a foundation of brick 
laid in mortar. The cutting and polishing, as well as the inscriptions, were finely executed. 
Its dimensions and inscriptions were as follows: Pedestal, including base, dado, and surbase, 5 
feet 6 inches high; the dado 3 feet 2^ inches square. The shaft was a pyramidal stone 10 feet 6 
inches high, terminating in an acorn-shaped ornamental top. On the dado were inscriptions as 
follows: North side: "Direction of the line," with carved arrow above, "United States of 
America" on a raised shield, a laurel wreath below. On south side similar decorations, with 
inscription in Spanish, "Direcion de la Linea," "Republica Mexicana." On east side: "North 
latitude 32° 31' 59.58," longitude 7'' 48'" 21. 1» west of Greenwich, as determined by Maj. Wm. H. 
Emory on the part of the United States and Jose Sala/.ar Ylarregui on the part of Mexico." On 
the west side: 

[uitialpoiiitofbonnilary lietween I'mito inicial tie limite entre 

tlie Uniti'd States aud Mexico, es- Mexico ylos Estados Uuidos, fi.jado 

tablislied by the Joint Commission i>or la Comision Unlda 10 de Octu- 

lOtU October, A. D. 1849, agreeably bre, A. D. 1849, segun el Tratado 

to the treaty dated at the City of coucluida en la Ciudad de Guada- 

Guiidalupe Hid.-ilgo February 2, A. lupe Hidalgo el 2 de Febrero, A. D. 

D. 1848. .John B. Weller, IT. S. Com- 1848. Pedro Garcia Conde, Coml- 

missioner. Andrew B. Gray, IT. S. sionado Mexicaua. .lose Salazar 

Surveyor. Ylarregui, Agrimensor Mexicana. 



174 UNITED STATES AND MEXICAN BOUNDARY. 

This monument had been so badly mutilated by visitors that some of the inscriptions had 
become illegible and the proportions of the stones seriously changed. Should the work of 
destruction have continued, the entire monument would eventually have disappeared. 

The other 5 monuments of this section were of cast iron and composed of thin jjlates 
riveted together. They consisted of a base, an inverted shallow box of iron, 3 feet square, a shaft 
2 feet square at base, 1 foot at top, 6 feet high, and terminating in a pyramid. The inscriptions 
found on the perfect monuments of this series wei-e as follows : North side, " Direction of the Lin(%'' 
"United States of America," also an arrow and shield. South side, arrow and shield, "Direcion 
de la Linea," " Republica Mexicana." East face, " Boundary between the United States and 
Mexico agreeably to the treaty of Guadalupe Hidalgo of Feb. 2, A. D. 1818." West face, " Limite 
entre Mexico y los Estados Unidos conforme el tratado de Guadalupe Hidalgo del \i de Febrero 
A. D. 1848." 

These monuments were located, respectively, as follows: 

No. II, about 5 miles east of the marble monument, in the valley of the Tijuana River, where 
the Mexican towu of that name has since been built. 

No. Ill, nearly 8 miles farther east, on Otay mesa, at the foot of the Coast Range. 

A long interval, including the whole mountain region, occurs before reaching No. IV on the 
west side of New River, in the middle of the Colorado Desert, distant from No. Ill about S2.'2 
miles. 

No. V on the east side of New River, 1.7 miles beyond No. lY. 

No. VI on the mesa south of Pilot Knob Mountain, near the Colorado, 43.5 miles east jpf No. V. 

Of the 5 iro7i monuments 3 had been destroyed, Nos. IV and V remaining in good condi 
tion, with the exception of their foundations, which were insecure. The latter apparently had 
been constructed of poles laid on the surface of the ground, and the monument fastened down 
by means of 4 iron rods passing through the base and anchored to pieces of wood embedded 
in the sand below. Had the sand been confined the method would have answered well. The sand 
had, however, drifted from beneath the bed of poles, and the monuments gradually settled, the 
ends of the bolts protruding several inches above the base. 

The iron bases, somewhat broken, of the 3 destroyed monuments were found in their proper 
places. These were resting on masonry foundations, but the superstructures had entirely 
disappeared. 

Of the 19 monuments shown on the maps of the second section, but 11 were found by our 
surveying parties; the other 8, if put up, had totally disappeared. All the monuments on this 
section, except No. II, located on the mesa east of the Colorado River Vsilley, were rude heaps of 
stone fragments, thrown together without mortar, and unprovided with inscription plates of any 
kind. 

Monument No. I, of this section, was shown on the map to have been located near the river 
bank 20 miles south of the junction of the Gila and Colorado rivers, but no trace of it could be 
found. 

No. II is an iron monunient which formerly marked an important reference point near the 
junction of the Gila and Colorado rivers, but had been moved to the new line established to 
comply with the terms of the Gadsden treaty. This monument stands on the edge of the mesa 
overlooking the Colorado Valley, and 2.7 miles east of that river. It is pyramidal in shape, 8 feet 
high, 2 feet G inches square at bottom, 1 foot 3 inches square at top, with a base 4 feet square, 
and, like those on the southern California boundary, is composed of thin cast-iron plates riveted 
together. Its foundation, like the others, was found defective, and is now replaced by masonry. 

Following the line eastward, Nos. Ill, IV, and V could not be found. It is possible they 
were never erected, as no trace of them exists, and it is hardly presumable that in this part of 
the desert, where a human being seldom passes, man's agency could have removed them. 

No. VI, a rude pile of stones, was found 101.2 miles east of No. II. 

Nos. VII and VIII, both originally located near the important Quitoba-quita Springs, were 
also missing. These had undoubtedly been destroyed by unknown persons and for unknown 
reasons. 



UNITED STATES AND MEXICAN BOUNDARY. 175 

Nos. IX and X were found — IX, 19.5 miles east of No. VI, and near the present settlement of 
Sonoyta; No. X, 14.6 miles east of IX, on the western spur of the Nariz Mountains. No. XI was 
missing. 

No. XII, on the eastern spur of the Nariz, was identified, and is 4.5 mUes east of No. X. 

No. XIII, 28.9 miles east of No. XII, located near the intersection of the road and boundary, 
and also near a precipitous rock, was so obscured by mesquite bushes that it was found with 
much difficulty. 

No. XIV was situated in the Moreno Mountains, a considerable group of hills, 12.3 miles 
farther east. 

No. XV, 17.1 miles eastward, where the line crosses the crest of the Pozo Verde Mountains, 
the southern extremity of the Baboquivari Range. This monument affords a conspicuous mark 
from both directions. 

No. XVI, 9.2 miles beyond, occupies a position on a hill in the rolling country near the western 
slope of the Fresnal Mountain. 

No. XVII, 2.6 miles from No. XVI, occupies the summit of the Fresnal and overlooks the 
adjoining country far to the east and west. 

Eighteen miles beyond, on one of the most rugged of the Pajarito Mountains, No. XVIII 
was located, the last authentic monument found on this section of the boundary. 

A small pile of rocks seemed to indicate the location of No. XIX on a high ridge near the 
angle at the Eastern end of this section, but was not accepted as a monument. 

The remaining section of the boundary was marked, as shown by the official map on file 
at Washington, with 27 monuments, while upon the Mexican official map there are 28. The 
discrepancy occurs on that part of the line along parallel 31^ 47'. The joint report of 1856 states 
that this line was marked by 10 monuments; the American copy of the map shows but 8, and 
the Mexican copy 9. Considerable confusion and uncertainty was occasioned by these differences. 
These monuments were numbered on the maps from the Rio Grande westward, the last number, 
27, upon the American map, being at the intersection of parallel 31^ 20' with the azimuth line, 
at the one hundred and eleventh meridian as shown on that map. 

The initial monument of this line stands on the west bank ot the Rio Grande, and at the 
date of our survey, 1892, was 172.6 meters from the center of the stream. When the location 
was made this distance was 71.04 meters, the channel of the river having moved 101.56 meters 
eastward since the location of the monument in 1855. The monument was built of cut stone, 12 
feet high, 5 feet square at base, 2 feet 6 inches square at top, and was found in fixir condition. 
The lower courses were somewhat disintegrated by the action of water, due to floods in the river 
or the wash from heavy rains pouring down the adjacent hillside. The following inscriptions were 
upon this monument: 

(hi till' north: On the south : 

V. S. R. M. 

Boundary accortling Limite cnnlorme 

to the treaty Ai tiatado 30 

of Deiember 30 de Deciembre de 

1853. 1853. 

East side: IVesI side: 

William Helmsley Emory Jose Salazar Ilairegiii 

American Commissioner. Comissionado Mexicana. 

Nos. 2 and 3 were found in good condition. No. 2 was 7111 meters west of No. 1, and located 
on the highest point where the line crosses the Mulero Mountains. No. 3 was 3.2 miles from the 
river at the edge of the wide mesa, which extends westward beyond the range of vision. These 
two monuments were pyramidal in shape, 5 feet siiuare at base, and built of rubble masonry, 
plastered on the surface with lime mortar, which had scaled oft" considerably. They were without 
inscriptions, but their height, 12 feet, and white color made them very conspicuous as boundary 
marks. 



17G UNITED STATES AND MEXICAN BOUNDARY. 

The next momimeut on this line was found 37.27 miles west of the river. It was much broken 
down, but from its shape and the several inscription stones found among- the ruins it was undoubt- 
edly erected as one of the marks of the boundary. It does not appear on the Emory map, but its 
approximate position is shown on the Mexican map, and accounts for the discrepancy in the number 
of monuments upon the two maps. 

The next monument was about 50 miles from the river. (This, like the preceding, does not 
appear on the Emory map, but one, no trace of which was discovered, is shown about 4\ miles to the 
east, on the summit of " Monument Mountain." The line falls to the south of this mountain, which, 
on account of its shape, we have called The Camel.) The monument was in bad condition, only about 
two-thirds of the original structure being in place. Plates of cut limestone, about 12 by 16 inches, 
contained the following inscriptions: On north side, the letters "U. S.;" on south side, "R. M. ;" on 
east, "W. H. E.""A. C.;" on west, " J. S. I." "C. M.," all well cut and perfect. It was built of irreg- 
ular and small fragments of stone laid partly in mud and partly in lime mortar. In dimensions it 
measured 5 feet G inches square at base, with a batter of about one in ten. Its height was originally 
12 feet. From this point the wide valley westward, in which lie the Palomas lakes, is overlooked. 

Thirteen and one-third miles farther west, and north of Lake Palomas, was found No. 5 of 
Emory's map. It was of the same general character as the former, including inscriptions, but in 
a more dilapidated condition. 

The next monument — iSTo. 6 of Emory's map — was found 8,2 miles west of No. 5, on the summit 
of the foothills south of the Tres Hermanas Mountains. It was of the same general character as 
the others and nearly demolished. 

Thirteen and four tenths miles farther west, and 2 miles south of the fine Carrizalillo Spring, 
Monument No. 7 of Euiory's map was found. This was in a demolished condition, though the base 
was well defined and the usual inscriptions, with one exception, were present. It was located on 
low ground, but near an old road, now little used, running south from the spring. 

East of this monument a distance of seven-tenths of a mile, and situated on a high ridge of 
the Carrizalillo Hills, was a square monument having vertical sides. This monument, being exactly 
on a line Joining Nos. C and 7, was believed to be a boundary mark, and the one necessary to 
complete the full number of ten reported by the joint commission of 185(5. It had )iot the ordinary 
characteristics of tlie otiiei- monuments and was without inscriptions. 

No. 8 of Emory's map, or No. of the Mexican map, and the tenth as actually found upon the 
line, marks the imi)ortant point which terminates the boundary along parallel 31° 47' and the 
beginning of the meridian section. It stands diagonally with reference to both lines, and is a flue 
cut-stone monument, in better preservation than the initial monument at the river. It was pro- 
vided with the same inscriptions and was substantially of the same dimensions. With the 
exception of its base and one stone of the lower course it required no repairs. 

Near the middle point of the meridian section, or about 15 miles south of the "corner," was 
found No. 9 of Emory's maji. This had been originally well constructed of rough stone laid in mud 
mortar, but was found in bad condition, the mud plaster having scaled oft" and many of the stones 
loosened. It had inscription plates of stone containing the initials "U. S.," "R. M.," " W. H. E.," 
and "-J. S.I." 

At the south extremity of the meridian line and the beginning of the boundary on parallel 
31° 20' was an excellent cut-stone monument in nearly perfect condition. Its dimensions were the 
same as those of the monument at the upper corner, as were also the inscriptions. 

The section of the boundary along parallel 31° 20' was originally marked, according to the 
Emory ma])s, with 17 stone monuments, numbered from 11 to 27, inclu.sive. Piles of stones, some 
bearing monument characteristics, M'ere found at fifteen points approximating to those given on 
the maps. Those corresponding to the positions of Nos. 11 and 24 were not found. 

No. 12 was a rude pile of loose stones, 28.6 miles west of the corner monument, on the eastern 
foothills of the San Luis range. 

No. 13, 3.8 miles farther west, marked the highest ])oint where the line crosses this range, and 
the highest on the entire boundary. 

No. 14, 3.4 miles beyond No. 13 and just west of the San Luis Mountains, was located near the 
important San Luis Springs. 




9. 




Old Monument between New Mexico 
AND Arizona. 



Antiguo Monumento entre Nuevo Mexico 
Y Arizona. 



UNITED STATES AND MEXICAN BOUNDARY. 177 

No. 15, only 3 miles west of the latter, had been placed on a long, low ridge, which ha.s every 
appearance of being an ancient artificial dam. 

The next mounment, No. 10, 13.3 miles beyond No. 15, was iu the Guadalupe Canyon where 
the wagon road crosses the bouiidary. 

No. 17 was on the Hat west of and near the San Bernardino River. It had no characteristics 
of a boundary monument except its position. 

Only 189 meters beyond, on the brow of the mesa, was No. 18. Though more distinctive than 
No. 17, it was badly dilapidated. Three of the old inscription plates, in a broken condition, were 
present. 

The next monument. No. 19, 9.8 miles farther west, was found in a range of hills which extends 
west from the Perilla Mountains, and near a prominent feature of the landscape known as the 
" Niggerhead," a steep, rocky mountain, almost inaccessible. 

Between this monument and the next one. No. 20, a distance of 42.8 miles intervenes. This 
stands near the west bank of the San Pedro Itiver, and is the monument erected under Major 
Emory's direction. Near this river, and occupying a bold promontory on its eastern side, was 
found another monument. Its position was 25" of arc, or about one half mile south of tlie 
boundary. This monument was built by Senor Salazar, the Mexican commissioner, after failing 
to find the one previously erected by Major Emory, and which tlie present survey shows to have 
been placed about 3" north of the true latitude. It was agreed between Major Emory and Senor 
Salazar, as expressed in their report, that iu case both these monunnuits were found to exist, the 
one erected by the American commissioner would be adopted. The San Pedro Kiver usually 
carries an insignificant amount of water, but during the rainy season is sometimes so swollen as 
to render it impassable. 

Nearly 18 miles farther west, just beyond the Huachuca Mountains, a scattered ])ile of stones 
was found, which corresjtonded sufficiently well with the position of No. 21 to be accepted as the 
site of that monument. It was upon a broad, open mesa, which extends several miles along the 
boundary, and is interseitted at frequent intervals by deep ravines. 

Two and eight tenths miles beyond No. 21, on the west side of a ravine through which Hows 
during the rainy season one of the sources of the Santa Cruz Eiver, was a pile of stones, which 
was decided to be monument No. 22. It had few characteristics to indicate its mission besides 
location, which was considered authentic. 

No 23, 5.J miles farther west, was found on a ridge overlooking the main valley of the Santa 
Cruz on the east, and a fine, grassy region on the west, in which is located the small settlement of 
La Noria. 

To the westward rise the sharp, rugged Patagojiia Mountains, on the summit of which, some 
5 miles distant, No. 24 is shown on Emory's map. No trace of this monument, however, could be 
found, the next one being No. 25, on the east side of the Santa Cruz River, where the boundary 
crosses this stream the second time after the latter has made its detour around the southern 
extremity of the Patagonia Mountains and taken a northerly course toward the Gila Valley. 
This monument was quite a large pile of stones, having regular form, but without inscriptions. It 
was distant from ^o. 23 14.7 miles. 

Five and six-tenths miles farther on, in the broken country beyond the Santa Cruz, No. 26 
was found. It was originally placed near the highway leading south into Mexico, which here 
runs through a beautiful, though narrow, valley containing good water near the surface. 

In later years a railroad has been built through this valley from Benson to the Gulf of 
California, and the thriving town of Nogales has grown up here, spreading out on each side of the 
boundary. The old monument occupies about the middle point of the settlement. When found 
it was but a rude pile of stones, though its base seemed to have been carefully laid with square 
corners, and some attempts made toward shaping the structure in the Ibrm of a pyramid. Badly 
defaced inscription plates were present. A building on the American side covered one-half of this 
monument, the sidewalk and street beiug on Mexican soil. 



178 UNITED STATES AND MEXICAN BOUNDARY. 

In reference to this subject the commissioners made a special report to the Department, and 
as the matter is considered important a copy of that communication is inserted : 

Department of State, 
International Uoundary Commission, 

United States and Mexico, 

Nogales, Ariz., Noremher 39, 1S92. 

Sir: The American members <if the Interuntiouul Bouiulary Coinmissiou beg respectfully to preseut for the 
consideration of the Department of State the following reconniiemlation with regard to the boundary between the 
United States and Mexico west of the Kio Grande: 

That a reservation not less than 50 feet be declared by the United States to extend along the entire length of 
the boundary on the American sidc^, and that the Republic of Mexico be asked to declare a lite reservation on the 
Mexican aide, and that the erection of buildings on either side of the line, witliin these limits, be prohibited by 
law; provided, however, that such reservations may be nsed for public streets or highways. 

The commissioners are deeply inipreascd with the importance of this measure, for the reason that the 
construction of private buildings near or upon the boundary atfords most favorable conditions for carrying on 
smuggling operations, to the detriment of both countries. 

At Nogales, on the American side, buildings have already been erected, and are occupied for business purposes, 
the south walls of which are on the line of the boundary, the old monument near the center of the town being half 
covered by one of these buildings. The Mexicans, with more generosity and modesty, have reserved a .space about 
50 feet wide south of the line, and which is now one of the priucipal streets of the town, business being carried on 
along this street by both countries. 

At Columbus, a new town recently established about 60 miles west of the Rio Grande, no buildings have yet 
been built near the boundary, owing, it is said, to previous uncertainty as to its exact location ; but now that the 
line is plainly marked, negotiations are on foot by interested parties to obtain ground on both sides and abutting 
on the boundary, for the purpose of erecting buildings that shall be located partly in each country. It is quite 
evident for what purpose buildings so erected are to be nsed. 

It is proijcr to state further that at Nogales general public sentiment favors a measure of this character; and as 
the title to the ground on which the town is located is soon to be adjudicated by the courts, with a strong probability 
of a decision in favor of the Government's ownership, it would appear that private interests will not suffer; but 
should this be the case to any extent, it is believed that such interests can be reconciled by the people themselves, 
as the buildings located on the boundary are few and of an inexpensive character. 

At Columbus the present proprietor of the lands on the boundary upon the American side is desirous of having 
a suitable reservatioh along the line devoted to a drive and park, and will offer no ob.jceti(m to a measure of the 
above character, provided the same width of land is set aside by the Mexican Government. 

These two are the sole points where towns have been established. 

The commissioners do not, of course, presume to suggest the method of arriving at the result desired, but 
simply as a matter of duty, and believing it, to be a question of grave i)ublic interest, they desire to present it for 
the consideration of the proper department of the Goverument. 
With the highest respect, your obedient servant, 

.1. W. Baislow, 
Liiutvnaiil-Coloiiel of E)igi liars, U. S. A., Commwsioner. 

Hon. John W. Foster, 

Secretary of Stale, Washington, D. C. 

Nearly 8 miles west of No. 20 was found the last of the monuments on this parallel. It was 
hidden away iu one of the deep valleys of the Pajaritos Mountains, and was almost concealed by 
a dense growth of bushes. This monument, No. 27, had inscription plates and was built with 
more care than many of the others on this part of the line, as it marked the point where the 
boundary changes its direction at the one hundredth and eleventh meridian, as then determined, 
leaving the parallel and taking an obliijue course toward a specified point on the Colorado River. 

It appears from the foregoing description of the condition of the old monuments at the time 
of the present survey that the boundary, originally marked with an inadequate number of monu- 
ments, many of them unsubstantial tind without distinctive features, had become almost obliter- 
ated. In one section the distance between authentic marks was over 100 miles, on another over 
80, while intervals as great as 10, ir>, and 20 miles were very fre(inent, giving rise to many disputes 
between miners, farmers, and herders, and permitting every facility and encouragement for 
smuggling. 

Through the more settled regions, notably along the southern California line, an approximate 
boundary had been adopted and rights acquired which in some instances were found to be 
erroneous, entailing loss and dissatisfaction to citizens on both sides when the proper boundary 
became known. These cases, happily, were neither numerous nor very serious. 



UNITED STATES AND MEXICAN BOUNDARY. 179 



CHAPTER VII. 

CONSTRUCTION AND. ERECTION OF NEW :M0NXTMENTS. 

The convention of 1882 between the United States and Mexico, revived by the convention 
of 1889, contained provisions with respect to the erection of new monuments. A full copy of 
these conventions will be found in the joint report of this commission. 

It was provided therein that the old monuments heretofore placed along the boundary should 
be restored in their original places; that new monuments should be set up at such points as might 
be necessary, and that the distance between two consecutive monuments should never exceed 
8,000 meters; this distance to be reduced on those jiarts of the line which are inhabited or 
capable of habitation. It was also provided that the monuments might be of stone in some 
localities, and in others should be of iron, the latter to be 6 feet high, with suitable inscriptions; 
also that the engineers in chief should determine the scientific processes to be adopted in prose- 
cuting the woi'k. 

In compliance with these provisions the two engineers in chief prepared a plan of operations 
for conducting the survey, and an agreement respecting the design, location, and erection of the 
necessary monuments to be placed upon old sites and upon new points to be selected. This plan 
of operations and the agreement are given in full in the joint report. 

Provision was therein made for determining the authenticity of all the old monuments found 
and the method of connecting thim by a line of new monuments placed at proper intervals. 

The monuments which have beeu rebuilt on the old sites are generally of stone, exceptions 
being two old iron monuments on the California line and one, also of iron, east of the Colorado 
River. These being in good condition, were repaired and retained. Another exception is the new 
iron monument placed on the site of an old monument at Nogales. 

The stone monuments were built in the form of an obelisk and are of the following dimensions: 
A shaft 10 feet high, 4 feet square at base and '2 feet at top, surmounted by a pyramid 1 foot 
liigli, a low foundation rising about G inches above the surface of the ground and o feet square. 
These monuments were built of sucii stone as could be found in the vicinity, the remains of the 
old monuments being generally used. Whenever stone of suitable quality could be obtained the 
fragments were roughly scjuared and made to conform to the batter of the structure, and when 
neatly pointed the monument presented a very good appearance. "Where only rough, refractory 
bowlders could be had, the surface of the monument was covered with a stucco of Portland 
cement plaster. The mortar used in the body of the work was composed of lime, cement, and 
sand. In all cases the iron inscription plates described in the agreement were put on in addition 
to the old plates found at the site of the monument. The iron plates were painted white and the 
whole monument given a coat of whitewash. 

The iron monuments are also obelisks, (> feet 6 inches high, 12 inches square at base, and 9 
inches at top. They are of two kinds: Those cast solid, for use on parts of the line which could 
be reached with wagons, and those cast in sections for convenience of pack transportation to less 
accessible positions. The weight in each case was 800 pounds, and the thickness of metal 2 
centimeters. Inscriptions in English and Spanish, as agreed upon, were placed on the north and 
south sides, respectively, of the monuments, and sockets for a flag staff on the west side of each. 
Consecutive numbers were also added on the east side after the erection of the monuments. The 
monuments were each bolted securely to the natural rock or to artificial bases of concrete 3 feet 
square and 2 feet thick. 

Two kinds of sectional monuments were used; the first, composed of a base, a cap, and 4 
side pieces, answered very well, but as the side plates were rather long for pack-mule transporta- 
tion, the design was changed for one composed of 7 pieces — a base plate and cap, such as in the 
other design, with 5 sections of shaft, the joints horizontal and rabbeted, each section U inches 
high, and made to fit over its neighbor below. The sections were held together by a wrought-iron 
bar 1 inch in diameter, connecting the base and top section. Above this was jilaced the pyramidal 
top, riveted to the section below, and concealing the bolt and nut. 



180 UNITED STATES AND MEXICAN BOUNDARY. 

This design was found to be much more convenient in every way than theotlier; the iiarts, 
being lighter and more compact, were easily handled and transported and were also assembled 
more readily, while the Joints were so nicely litted that the appearance of the monument when 
erected was practically the same as that of those whicii were cast solid. 

The castings, including inscription plates and the necessary bolts, washers, numbers, etc., 
were all neatly prepared at El Paso, Tex., by the Foundry and Machine Compajiy of that place, 
W. N. Small, president, and were in every way satisfactory. The iron was tough, resisting the 
rough handling incident to transportation by rail, wagon, and pack train without accidents, while 
the surfaces and the lettering, some of it very small, were as perfect as any work of a similar 
character turned out in more eastern establishments. 

The cost of iron monuments, including inscription plates, numbers, bolts, washers, etc., ready 
for shipment, was about $40 each. Their transportation and erection, including cost of concrete 
bases, added from $100 to $110 to each moTiuraent, making the total cost in place about $150 each. 
The average cost of stone monuments was about the same. 

The new monuments were located under the personal supervision of the engineers in chief. 
They were not placed at arbitrary intervals, but always upon the highest ridges, and at snch 
distances apart that they are practically intervisible. To secure tiiis result more perfectly each 
monument is provided with sockets, in which a high tiagstaff can be inserted to show above small 
intervening obstacles. 

1. Faxillel i'i^ 47' and the meridluu section. 

|i:iO miles, 53 mniiinnents.) 

The section of the boundary from the Itio Grande along the parallel of 31° 47' and on the 
meridian to the i)arallel of 3P 20' having been surveyed by the American and Mexican engineers, 
the results compared and accepted August 10, 1802, the work of preparation for the erection of 
monuments was immediately begun at El Paso. 

The transpoitation for the monument building party was detacheil from the main camp at San 
Bernardino, Ariz., August 6, 1892, and sent under charge of T. II. Logan, quartermaster, to El 
Paso, Tex., a distance by wagon road of about 240 miles. It followed the road via the Guadalupe 
Canon, thence to Sei>ar, on the Southern Pacitic Railway, along which it continued to its 
destination, where it arrived on the lltli of the same month. 

The train consisted of four baggage wagons, one water-tank wagon (capacity 400 gallons), and 
a light spring wagon for instruments; an additional spring wagon, with horses, was purchased at 
El Paso. 

The organization of the American party consisted of one commissioner, one assistant 
engineer, one rodman and helper, which, with a similar Mexican party, was charged with the 
location of monuments. Each party had also a photograi)her to take views of monuments. The 
building party, wholly American, included a mason, a blacksmith, and several laborers, team- 
sters, cooks, etc., to perform the work of erecting monuments. 

Monument No. 1, which is the old initial monument on parallel .'51^47', stands on the west 
baidv of the Kio Grande, 172.6 meters from the center of the channel. A description of this and 
all other old monuments has been given in the preceding chapter of this report. 

The repairs upon this monument comprised the addition of a .jacket of cement mortar, 4 
feet high above the base, to protect the stones from further disintegration; repointing the joints 
with cement, and adding four small plates of marble, with inscrii)tions as follows: 

On north side: "n xmilk siiie: 

Repaired by the Keiidvadu por la 

Boundary Commission Coniision de Limites 

Created by treaties of Creada per los tratados de 
1882-1889. 1882-1889. 

On east and west sides the penalty notice, in English and Spanish, respectively. On the east 
side was also cut in one of the old stones of the shaft the number "1." These repairs were 
completed August 29, 1892. 

Nos. 2 and 3 are also old monuments. They were originally covered with a lime coating, 
which had scaled off in places, and had also been much disfigured by visitors. These two monu- 



UNITED STATES AND MEXICAN BOUNDAKT. 181 

ineiits were repaiit'd by removing as much as possible of the old plaster, recoating them with 
durable cemeut mortar, and placing on the uortli and south sides, respectively, the iron inscription 
plates in English and Spanish prescribed by Section III of the additional agreement dated March 
9, 1802. subsequently modified by the addition of the penalty notice above referred to. 

Similar cast-iron plates were placed on all masonry monuments, except No. 1, rebuilt or 
repaired by the present commission. Consecutive numbers were also placed on the east side of 
each monument, both old and new, from the Rio Grande to the Pacific Ocean, except along the 
meridian section, where these numbers were placed on the north side and the inscription plates on 
the east and west sides, respectively, and sockets for flagstaft' on south side. 

It having been agreed by the joint commission that the positions of old monuments after 
verification would be accepted and tliatnew monuments should be placed on the proper connecting 
lines, the tangent parties of each section located tlieir respective tangents, marking them at 
frequent intervals with substantial stakes. It remained, therefore, for the monument party to 
calculate and measure the necessary offsets from these tangents to the points selected for 
monuments and to compare the results. For formuh^ and details of computation see Geodesy, 
Chapter IV, and its a[)pendices. 

When the two points so determined for each monument by the American and Mexican 
engineers diflered in position more than 2 meters, remeasurements or recalculations were made 
until the error was discovered and the discrepancy reduced. The largest discrepancy which was 
allowed to remain on the parallel of 31o 47' was 1.30 meters at Monument No. 10, the Mexican 
determination falling south of that of the United States. The average difference between the 
United States and Mexican locations for the new monuments on this line was 0.43 meter. On 
the meridian, the United States line, being considered perfect, was adopted by the Mexicans. 
In all cases the monument was placed midway of the two determinations. 

On September 7, 1802, No. 4, the first new iron monument, was erected on the mesa 7,582 
meters west of No. 3. The surrounding country is characteristic desert, being a succession of low 
.sand hills carrying a scant growth of cactus, yucca, and greasewood, with an occasional mesquite 
bush. 

The manner of setting the iron monuments in place when concrete bases were required was 
as follows, and was substantially the same along the whole line. 

After the exact location had been determined by the engineers of the joint commission, and 
the necessary stakes driven to mark its position, the soil was excavated to a depth of 2 feet 
and the base box put in place. This consisted of four sides, inclosing a space 3 feet square 
and 2 feet deep. The box was carefully adjusted in jjosition and accurately leveled. An iron 
template, containing four liuch holes, corresponding exactly with those in the base of the 
monument, was fastened by means of small bolts and nuts to tlie top of the box. The anchoring 
bolts were now placed in the box, their upper ends p issing tlirough the holes in the template. 
The box was then filled with concrete in layers thoroughly rammed. This mixture was formed 
of one cask (400 pounds) of Portland cement, a double (inantity of tiie best sand obtainable, and 
a sufticient quanitity of gravel or broken stone to make up the required 18 cubic feet of material. 
About 30 gallons of water was necessary to give the requisite moisture. Allowing several hours 
for the concrete to harden, the tenqilate and box were removed and the monument put upon its 
base. The bolts passed easily through the four holes in the flange of the monument; the nuts, 
which were cylindrical, were screwed down with a pipe wrench, and the ends of the bolts riveted 
above them. A coat of paint had been given the monument before leaving the shop, and 
immediately after its erection and the attachment of the api)ropriate numbers another coat of 
white paint was added. 

In moving out from El Paso the monument party encountered great difficulties, owing to 
the heavy loads to be carried over the soft, yielding .sands of the desert. For 50 miles west 
of the river no water was found near the line, and a su|)ply had to be sent out in advance, together 
with several monuments and casks of cement. This labor tasked the limited transportation 
appropriated to the monument work to its utmost capacity, the strain upon the animals being 
excessive. 

It was not until the 14th of the month that the party was able to cut loose from the river 
and push out into the desert. It was then found that the provision for supplying water was 



182 UNITED STATKS AND MEXICAN BOUNDARY. 

iuadequate, and an additional water tank was fortunately obtained by hire until another could 
be constructed at El Paso. With the aid of the second water wagon the work was pushed on 
without detention. The next water near the line, after leaving El Paso, is at Wragg's ranch, 
50 miles distant, the vicinity of which was reached on the 27th instant, thirteen days after 
leaving the river at El Paso. 

Monument No. 5, new iron, was erected on the 14th of September, 7,547 meters west of No. 4. 
The difterence between the United States and Mexican offsets here was 1.36 meters, the United 
States determination falling south of the Mexican. The surrounding country at this monument is 
much the same as at No. 4, being a continuation of the desert mesa, with its characteristic 
vegetation. 

Through this worthless region, where boundary disputes are not likely to occur, the distances 
between the monuments were made as nearly as possible to reach the limit of 8,000 meters 
provided by the convention, but in no case was this limit exceeded. 

The sites of Nos. 6 and 7 were in all respects similar to those for 4 and 5, except that grama 
grass began to appear in sufficient quantities to afford some grazing for the animals when they 
could be spared from their work to take advantage of it. 

No. 8 occupies a high, rocky, and sandy ridge, a spur from the Potrillo Mountains, which lie 
immediately north of this point, and No. 9, about 1,400 meters distant, was placed upon the crest 
of another high ridge beyond a deep ravine. It being desired to place the monuments so that 
they would be practically intervisible, it was necessary in this case to locate one on each of the 
two adjacent ridges. 

On September '20 the monument party camped near an old monument (No. 4 of the Mexican 
map) and immediately established communication with Wragg's well, about 15 miles distant. The 
water (piestion had become very serious. The two tanks now in u.se, and all available barrels, 
were kept moving between the line and the railroad, requiring journeys of from 10 to 20 miles over 
very difficult and sandy roads to keep the camp and its animals supplied with sufficient water. On 
some days the failure of a wagon to arrive on time would have resulted in a water famine that 
would have been disastrous. 

The weather was extremely hot, and when short rations had to be enforced both men and mules 
seemed to require a double allowance. It was necessary to retain the camp at this place until the 
24th to complete the unfinished work on iron Monuments Nos. and 10, and to construct stone 
Monument No. 11, the latter to occupy the site of the old monument at this point. 

No. 10 fell among sand hills and mesquite bushes near a wide ravine 7,027 meters west of No. 
9, and 7,811 meters east of No. 11. The chief characteristic attending its erection was the heavy 
hauling through the sand hills. 

After the return of the first water wagon sent to Wragg's well, which occurred on the evening 
of the 22d, and proved the practicability of obtaining water from that source, it was felt that the 
critical period had passed, and that work could go on without special anxiety on account of water. 

The work of surveying this part of the line, i)erformed during the preceding spring, was 
attended with much inconveuieace on account of tlie scarcity of water; but with the monument 
party the conditions were even more trying, as the work was of a nature that required a large 
number of men and animals to be kept together to handle and transport the monuments, cement, 
etc., in addition to the usual supi)lies. 

On the 24th, the work as far as No. 11 (stone monument) having been completed, a small 
force was left to finish the construction of this monument, and the cauip moved 6 miles farther 
west and nearer the now water supply. 

No. 12 was located on the mesa 3.2 miles west of No. 11, and No. 13, 4.3 miles beyond on the 
southern slope of a ridge near a high mountain called, from its shape. The Camel. 

Camp was moved on the 27th west of this mountain and near the location of No. 14, which 
marks the crossing of the line over a high, sharp ridge about 3 miles west of No. 13. From this 
point, looking eastward just before sunset, the line as marked by seven or eight monuments is 
plainly visible, showing the curvature of the parallel for a distance of over 20 miles. 

No. 15, 2 miles west of No. 14, was rebuilt of stone on tlie site of the old monument, and was 
finished on the 30th. From this monument a view to the west extends across a broad valley in 



UNITED STATES A.ND MKXICAN BOUNDARY. 183 

wliich are located the shallow alkaline lakes kuown as Las Paloinas, and near which the Mexican 
settlement of that name is situated. 

Just north of these lakes, and adjoining the boundary, has been laid out on the American side 
the town of Columbus. Should the expectations of its founders in obtaining a railroad from tiie 
Southern Pacific line at Deniing, the grading for which has been done, ever be realized no doubt 
a village of some importance may be built here, as the soil is fertile and, except in dry seasons, the 
grass is abundant. Beyond cattle raising, an industry badly crippled by the late droughts, no 
business is being carried on in this region. 

Monument erection now continued rapidly across this plain. Iron Monument No. 16 was 
placed on a low ridge 1,6(J0 meters west of No. 1.5, and Nos. 17, 18, 19, and 20 followed at intervals 
of about 4,000 meters each. 

No. 21, occupying the site of old No. 5, was rebuilt of stone, its location being about 2 miles 
beyond No. 20. Nos. 22 and 23 were placed 1 mile apart, and where the section lines east and 
west of the town of Columbus, respectively, intersect the boundary. No. 24, 4,445 meters west of 
23, was located on a rugged mal pais ridge, and No. 25, 3,820 meters beyond, was placed on the 
slope leading to the hills south of the Tres Hermanas Mountains. 

On the summit of these hills, and 1,331 meters beyond No. 25, old No. 6 of Emory's map was 
rebuilt of stone in the usual manner and numbered 20. From this point another fine view is 
obtained, looking westward across the valley intervening between these hills and the Carrizalillo 
Mountains, a distance of about 11 miles. 

Along the line crossing this plain were placed iron Monuments Nos. 27, 28, 29, and 30, at 
intervals of about 3,600 meters. This region is characterized by a soft, sandy soil yielding the 
ordinary desert vegetation, including greasewood and several varieties of cacti. 

No. 31, upon the first ridge of the Carrizalillo Mountains, 3,436 meters west of No. 30, occupies 
a commanding position overlooking the valley to the eastward. The transportation of the 
monument to this elevated location was attended with considerable difficulty. 

No. 32, 2,442 meters farther west, is a stone monument built on the site of what was 
considered one of the original nionunients, and the eighth in order from the Eio Grande. It is 
situated on the highest point where the line crosses these mountains, and afifords a magnificent 
view of mountain scenery in all directions. 

In the valley, less than a mile west of this monument, is No. 33 — also a stone monument — 
built on the site of old No. 7 of the Emory map. It was originally located near the wagon road, 
leading south from tiie Carrizalillo Siirings, at one time much traveled, though during later years 
it has been but little used. 

The erection of monuments was completed to this point October 17, 1892. 

A plain about 10 miles in width and abounding in a heavy growth of mesquite extends 
westward to the Apache Mountains. Along this part of the line were erected iron Monuments 
Nos. 34, 35, 30, and 37, about 2i miles ajiart. 

On the most eastern ridge of the Sierra Kica Mountains No. 38 was located, 2,597 meters west 
of No. 37. This ridge slopes to the northward, and its steep, rocky scarp rendered the work of 
hauling the monument to its position very trying upon the animals and men. 

No. 39 -was placed on another sharp ridge sloping southward and 2,784 meters further west. 

No. 40, marking the extremity of the boundary along parallel 31° 47', and 2,060 meters from 
No. 39, is the old cut-stone Monument No. 8 of the Emory map. The present measurements and 
astrononiical determinations show that this monument was originally located 54.38" of longitude 
too far east, thereby causing this section of the boundary to be 1 mile less in length than was 
provided by the treaty. 

This monument and Nos. 38 and 39 mark a part of the line which passes through what was 
once considered an important silver-mining region; many prospect holes on both sides of the 
boundary are still evidences of the work done here by miners, and some of the claims are yet 
considered valuable. No work, however, is now being carried on, and the general opinion is that 
the low grade of the ore precludes profitable working under the disadvantageous conditions that 
now exist. 

From No. 40 the boundary runs due south about 31 miles, connecting the parallel of 31° 47' 
with the parallel of 31° 20'. On this meridian section 11 iron monuments were placed at intervals 



184 UNITED STATES AND MEXICAN BOUNDARY. 

of about 2i miles. Old Monument No. 9, midway of the meridian, was afterwards rebuilt of 
masonry and numbered 46. 

No. 41 was ijlaced on the highest point where the meridian crosses the Sierra Hica, about 2 
miles south of No. 40. It occupies a bold, rocky ridge, from which grand views to the north, south, 
and west are obtained. Northwest are the Hachita Mountains ; west and southwest the vast range 
of the Sierra Hacha, including the "Big Hatchet," the most prominent mountain in this vicinity, 
while to the south the meridian line of the boundary is unobstructed almost to its southern 
extremity. 

From No. 41 the line of monuments descends gradually about 12 miles, passing a mile west 
of the Mosquito Springs, a very valuabhi and important water source much used by travelers as 
a camping place; it also supplies large herds of cattle and horses with drinking water. 

Iron Monuments Nos. 42, 43, 44, and 4.5 were placed along this part of the line. From 41 to 
5- the intervals are between 2 and 3 miles. 

Nos. 47, 48, 49, 50, 51, and 52 continued the line south over a comparatively level country, but 
much obstructed in places, especially in the vicinity of the Mosquito Springs, by a heavy growth 
of mes((uite. 

No. 52, the last of the iron monuments on this section, occupies the only ridge of importance 
south of No. 41, and was placed at 542 meters from the monument marking the south extremity 
of the meridian section. 

The monument party completed the erection of monuments along the parallel of 31° 47' on 
the 24th of October, and as the first iron monument was put ui) on the 7th of September, this line 
was marked in about forty woiking days, duiing which time 30 iron monuments were placed and 
stone monuments built, being an average of one and one third days for each iron monument 
and about seven days for each stone monument. 

During the latter part of October and the beginning of November the weather was extremely 
unpleasant; rain and snow fell in nnprecedented quantities, making the roads in i)laces almost 
impassable, and seriously retarding the progress of the work. The 11 iron monuments along the 
meridian were all put up by the 10th of November, the average time per monument on this part 
of the boundary being about the same as on the parallel. 

To add to the annoyance and inconvenience at this time, rumors of the near presence of the 
Apache "Kid" and his band were rife, and as the whole monument party with its escort was not 
large the men's anxiety on this account was not unreasonable. 

Owing to these sevcntl difficulties it was decided to omit the rebuilding of the old monuments 
on the meridian until work siiould be resumed on parallel 31" 20'. The work on tliis parallel 
could not be taken up at this time owing to the fact that no agreement by the joint commission 
had then been reached in regard to its details. 

Accordingly, on the 12tli day of November the monument party, with its transportation, 
discontinued further work and moved westward along the boundary, joining the main camp two 
weeks later at La Noria, on the Santa Cruz River. The men and transportation were employed 
with this party in its operations westward until they were again required to take up monument 
work the following year. 

During the entire progress of the work the photographer accompanied the working party, 
and made two or more views of each monument after it was erected. 

The transportation was increased during the progress of the work by the addition of one 
baggage wagon and one water tank wagon, the mules being supplied from the pack train sent from 
the main survey camp in September. 

The boundary on parallel 31° 47', 99 miles, is marked by 40 monuments, numbered 1 to 40 
inclusive — 30 solid iron, G new masonry on old sites, and 4 old monuments rei)aired; average 
distance apart, 2.5 miles; maximum, 7,94.S.3 meters; minimum, 713.4. The meridian section, 31 
miles, is marked, in addition to No. 40 at the corner, by 13 mouuraeuts; 11 are solid iron, 1 new 
masonry, and 1 old masonry repaired; average ilistance apart, 2.4 miles; maximum, 4,772.91 
meters; minimum, 542 meters. 

The greatest difference between the United States and Mexican offsets occurred :it No 10, the 
Mexican position falling 1.39 meters south of the American; and at No. 5, where the .Mexican 



UNITED STATES A^D MEXICAN BOUNDARY. 185 

poiut fell 1.36 meters uortb of the American. On the meridian line the positions were identical, 
the American determinaticms having been adopted. 

The organization of the monument party upon this work was as follows: Col. J. W. Barlow, 
commissioner, in general charge; E. L. Ingram, assistant engineer in charge of location; T. H. 
Logan, in charge of erection of monuments and transportation; D. li. Payne, photographer and 
general assistant; 1 rodman, 7 teamsters, 4 laborers, 1 blacksmith, 1 stone mason and 1 helper, 1 
cook and 2 helpers. 

The transportation consisted of i baggage wagons (afterwards 5), 1 water tank wagon 
(afterwards 2), 2 spring wagons, 1 buckboard, and 2 saddle horses; 15 pack mules were added and 
assigned to teams. 

A hand truck and a sectional iron tripod, with differential pulleys, were provided for use in 
setting the iron monuments in position, but were soon abandoned, it being found more convenient 
and a saving of time to place them by hand. 

The escort consisted of two mounted cavalrymen, for courier duty, and a guard of three 
noncommissioned officers and nine privates of the Twenty-fourth Infantry under the command of 
Sergeant Curtis. The escort was provided with one baggage wagon. 

2. Parallel 31'^ 20'. 

1170 miles, 7i munumratH.] 

Early in the spring of 1S93 the joint commission came to an agreement with respect to the 
survey of the line along the parallel of 31'^ 20'. Preparations were then begun to take up the 
work of building monuments upon that part of the boundary. The boundary upon this parallel 
connects the southern extremity of the meridian section with the eastern end of the azimuth line 
at the one hundred and eleventh meridian, as established by Major Emory. 

In May, 1893, a monument building party, similar in strength and equipment to that of the 
previous year, was detached from the nniin camp at Yuma and sent overland to Nogales, Ariz., 
where the final preparations for the work were effected, with the intention of working eastward 
from the one hundred and eleventh meridian to the meridian section. 

This party consisted of one commissioner. Col. J. W. Barlow, in general charge, with Mr. B. 
A. Wood, assistant engineer, in charge of location, T. H. Logan in charge of erection of monu- 
ments, D. E. Payne, photographer, 2 rodnien, 1 blacksmith, 1 stone mason, 5 teamsters, 5 laborers, 
1 cook, and 2 helpers. The transportation included 2 water-tank wagons, 3 baggage wagons, 2 
spring wagons, 1 truck wagon, .'") horses, and 21 mules, which with some minor changes was 
maintained during the season. An escort of 10 men. Second Cavalry, and 10 men, Twenty-fourth 
Infantry, Second Lieut. George II. McMaster commanding, accomi)anied this party. 

The truck wagon was specially prepared for hauling a single monument, with cement and 
water sufficient for its base, over almost any kind of country. The bed was hung beneath the 
axles near the ground, making the wagon so stable that it was frequently driven along rocky and 
steep mountain sides in places where mules could hardly find a footing. 

From the careful profile and topography which had been made of this line it was possible to 
select all the positions for the location of monuments with such near ai)proximation tliat the 
proper numbers could be placed upon them in advance without error, so that the work could be 
carried on from the west in the reverse order of the numbers. 

Necessary preparations having been completed, the work was begun June 17, 1893. It was 
first carried westward along the i)arallel of 31° 20' as far as the angle at the one hundred and 
eleventh meridian, a distance of about 8 miles, and then eastward along the parallel to the 
meridian section of the boundary, where the work terminated the previous year. 

The time occupied in the work on the parallel of 31° liO' was from the Kith of June until the 
19th of September, 1.S93, when the most easterly monument on this parallel was erected. 

The three old monuments which originally marked the meridian section, the repair of which 

had been deferred until the present season owing to inclement weather, were now rebuilt or 

repaired, and the entire work in this region was finished by the close of September, when the 

party and transiwrtation were taken overland to Tucson, Ariz., to reorganize for the work ot 

S. Doc. 247 15 



186 UNITED STATES AND MEXICAN BOUNDARY. 

erecting monuments on the azimuth section of the boundary from the one hundred and eleventh 
meridian westward. 

The monument party encountered this season an unprecedented rainy period. During the 
two preceding years hardly a drop of rain had fallen along this section of the boundary, and 
in consequence the country had a burned, barren appearance; nearly all the water courses 
had become dry; grass had disappeared; cattle by thousands had perished. This season the 
conditions were entirely changed; rain fell copiously and at very frequent intervals. The 
water courses were flooded, and the country took on a covering of green, iu marked contrast to 
its former desert appearance. The few remaining cattle became fat and sleek, and grass soon 
grew in such quantities tliat vast fields were cut with machines, and hay soon became cheap 
and abundant. 

The heavy rains, however, caused the monument i>arty considerable inconvenience and 
somewhat retarded operations. The streams, which the previous year were dry ditches, now 
became at times impassable, and the former hard roads soft, bottomless quagmires. The weather 
was, however, generally cool and agreeable, so that men and animals thrived in spite of the 
hardship and exposure to which they were subjected. 

Old Monument No. 8, at the northern extremity of the meridian section, was taken down and 
rebuilt in order to restore the injured foundation. The same stones were replaced in their original 
positions, leaving the external appearance but little changed. Iron inscription plates were added, 
and also the new number, 40, to conform to the present series. 

Old No. 9, midway of the meridian section, was entirely rebuilt of masonry, iu accordance 
with the adopted design for stone monuments. The material of the old monument was used, new 
inscription plates added, and the monument numbered iG. The monument at the south end of 
the meridian section was in such good condition that but minor repairs were necessary. It was 
repointed with cement mortar and inscription plates and the appropriate number, 53, added. 

The first 10 monuments west of the lower corner on parallel 31° 20' are of iron. No. 54, 2| 
miles west of No. 53, and No. 55, 4^ miles still farther west, were located on low ridges in a 
comparatively level area extending to the Dog Mountains. No. 56, li miles beyond, was 
placed on the first ridge of the Dog Mountains. 

No. 57, a sectional monument, 2^ miles distant from No. 5G, marks the highest point of the 
line as it crosses these mountains. No. 58, SJ miles beyond, was located on another prominent 
ridge, and No. 59, 1| miles still farther west, upon a third ridge at about the same elevation as 
No. 58. 

In the Playas Valley, west of the Dog Mountains, and marking its lowest depression, No. 60 
was placed, 4 miles distant from No. 59. No. 61, on a high ridge of the Whitewater Hills, 3.J miles 
west of No. 60, overlooks the Playas Valley to the eastward, and No. 62, Ij miles farther west, 
stands on the south slope of another prominent hill of the Whitewater group, and commands a 
fine view over the western arm of the Playas Valley. It is supposed that old No. 11 was located 
in this vicinity, but no trace of it could be found. No. 63 marks a point in the Playas Valley 2 
miles west of No. 62. 

No. 64, on the eastern slope of San Luis Mountains, 2J miles beyond No. 63, was built of 
masonry on the site of old No. 12. 

No. 65, a masonry monument, on the site of old No. 13, stands 3| miles west of No. 64 upon 
the summit of the San Luis range, and enjoys the distinction of being located on the highest 
point of the entire international boundary. This altitude is 2,048.3 meters, or over 6,700 feet, 
above sea level. From this point a magnificent view extends in all directions. Eastward, over 
the Whitewater and Dog mountains to the Boca Grande range, 50 miles distant; while westward 
the whole country as f\vr as the Huachuca Mountains, 100 miles away, is spread out like a map. 
The mountains in the immediate vicinity are rough and broken and the ascent to the site of the 
monument steep and difi&cult. 

No. 66, also a masonry monument, was built on the site of old No. 14, just beyond the western 
foot of this range, and 34 miles west of No. 65. It stands south of the important San Luis 
Springs, which are extremely valuable to the ranchers in this region. 



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UNITED STATES AND MEXICAN BOUNDARY. 187 

No. 07, still another masonry monument, marks the location of old No. 15. This is 3 miles 
west of No. G6 and stands about midway of Las Animas Valley on a low ridge, which is supposed 
to have been constructed as a dam by some prehistoric nation. Its height and great width 
reipiired an amount of labor on the part of those ancieut people which seems out of all proportion 
to tlie capacity of the country to support a large population. 

The San Luis and Guadalupe ranges and adjacent valleys are favorite resorts for the few 
marauding Apache outlaws remaining in this country. Apache *'Kid," whether justly or not, has 
been given a special notoriety as a desperate and dangerous bandit who habitually wanders 
between the San Carlos Keservatiou and certain strongholds in the Mexican Sierra Madre. Using 
these mountains as a highway, he has effectually eluded the many search parties that have been 
sent in pursuit of him. In traveling through the country he preys upon the ranchers, stealing 
horses and cattle and occasionally committing murder, when he finds it to his interest to do so. 

Members of the monument party at difl'erent times believed this notorious character to be 
hovering in their vicinity, and on one or two occasions several Indians were seen whose suspicious 
actions gave rise to the conclusion that the veritable " Kid," with a few followers, was watching 
their movements with a view to an ambuscade. He gave us no trouble at any time, although the 
scattered condition of our parties aftbrded many excellent opportunities for an attack. It is 
believed that the "Kid" never incurs any personal risk, committing his depredations only under 
conditions which insure his own immunity. 

Beyond No. 07 five iron monuments were placed in succession: No. 68 in Las Animas Valley, 
2 miles beyond No. 67; No. 60, 3 miles further west, the latter near the foothills of the Guadalupe 
Mountains. Two miles west of No. 69 No. 70 was placed on a very high peak of the Guadalupe 
Mountains, from which a grand and interesting view of mountain scenery is obtained. The steep 
and rugged slope of this mountain rendered necessary the use of a sectional monument at this 
point, the pieces being carried to the site on pack mules. No. 71 was located at the point where 
the line between New Mexico and Arizona intersects the international boundary; it stands 3^ 
miles west of No. 70, on the side of a high mountain and near the bottom of a deep ravine. This 
was also a sectional monument. No. 72, another sectional monument, was placed upon the 
summit of an extremely high, precipitous mountain, and about three-fourths of a mile west of No. 
71. It occupies a site from which is visible a vast extent of broken, mountain country. 

On the site of old No. 16, in the bottom of the Guadalupe Canon, where the old road through 
this canon crosses the boundary. Monument No. 73 was built of masonry. Its position is about 
l.J miles west of 72, and is near a high, rock bluff, around which the road curves in an easterly 
direction after passing the monument. The ranch house of Mr. Hall, an American who owned 
considerable property in this vicinity, was located in the canon near this monument. 

The Guadalupe Canon is specially notable from the fact that it affords the only practicable 
pass for wagons within a distance of 50 miles to the north, and a much greater distance in the 
otlier direction; and as the boundary runs near the canon it was of the utmost value in 
conducting the work of surveys and monument erection. 

Nos. 74, 75, and 76, iron monuments, were placed on the mesa west of the Guadalupe 
Mountains at intervals of about 3 miles. The country here is rolling and the soil hard gravel and 
sand, yielding a moderate growth of grass beside the usual varieties of cacti. 

No. 77, a masonry monument, stands on the mesa just west of the San Bernardino River and 
occupies the site of old No. 18. It was built of the fragments of that monument and ijrovided 
with the usual inscriptions. Its altitude is less than that of any other monument on this parallel, 
being 1,132.6 meters above sea level; the river valley just east of it is somewhat lower. On this 
low ground near the river are the remains of old No. 17. This monument was not rebuilt. 

The San Bernardino Valley at this place is flat and marshy, covered with grass, and has 
several springs of good water, also a number of quite large pools. At one time it was the site 
of a Mexican hacienda with flourishing ranches in its vicinity, nearly all now abandoned owing to 
the depredations of the Apache Indians and the malarial condition of the climate. 

No. 78, an iron monument, was placed 1^ miles west of No. 77 on a low ridge, and No. 79 3^^ 
miles further west on one of the foothills of the Perilla Mountains. No. 80, a sectional iron 
monument, was located nearly 3 miles west of No. 79 upon a high, commanding ridge of these 



188 UNITED STATES AND MEXICAN BOUNDARY. 

mountaius. It overlooks the valley of Sau Bernardino and a large extent of country both to the 
northeast and southeast. The maximum difference in the offsets on this parallel between the 
United States and Mexican determinations occurred here, amounting to 1.6 meters, the Mexican 
position being south of the American. 

No. 81, another sectional monument, was located less than 1 mile west of No. 80. It occupies 
the highest point of the line iu crossing the Perilla Mountains and affords a superb view in all 
directions. 

About 1 mile farther west, among the hills leading toward the Sulphur Spring Valley, No. 82 
was rebuilt of masonry on the site of old No. 19. It stands near the road connecting the San 
Bernardino and San Pedro valleys. To the southeast of this monument is a conspicuous land- 
mark known as the "Niggerhead," a tall, steep rock surmounting one of the highest mountains of 
this range. The Mexican name of this peak is Cerro Gallardo. 

From the Perilla Mountains to the San Pedro River, a distance of about 42 miles, the line 
was marked with 15 solid iron monuments, at intervals varying from 1 to i miles, the average 
being about 3 miles. 

The country along this part of the boundaiy is unobstructed by mountains or deep ravines, 
and but for the severe rains which occurred during the period of operations the transportation 
and erection of monuments would have been attended with little ditticulty. The most serious 
obstructions were in the low valleys, especially at the Sulphur Spring bottom, where, owing to the 
almost constant rains, the roads were at times nearly impassable. The rich soil of these valleys, 
stimulated by the heat and unusual moisture, produced iu a few days a growth of vegetation 
bordering upon the magical. 

No. 98, near the western bank of the Saii Pedro Kiver, was rebuilt on the site and from the 
remains of old No. 20. 

The San I'edro River flows through an alluvial valley iu which are located numerous ranches. 
About 7 miles south of the boundary is a small Mexican village, San Pedro, which until recently 
contained the Mexican customhouse, since moved to La Morita. The bed of the stream has been 
sunk by the attrition of the current 8 to 15 feet below the surface of the ground, and is from 30 to 
(')() feet in width. In ordinary seasons but little water is found in the stream, but during the 
operations of the monument party in this vicinity, heavy Hoods caused the river frequently to rise 
l)ank full, and as there are no bridges its depth at times seriously interrupted comuiuuication 
between oi)posite banks. 

Three and one half miles west of the river No. 99 was located on the ascending slope of the 
mesa toward the Huachuca Mountains. Nos. 100, 101, and 102 were placed high up on spurs of 
tliese mountains. They are all sectional, their parts having been carried to their locations on pack 
animals. They are specially notable on account of their high altitude and the rough and rugged 
nature of the adjacent country. No. 100 occupies the most easterly spur or ridge, at a distance of 
3 miles west of No. 99, and is 1,840 meters above sea level, commanding an extensive view to the 
east as far as the Per.Ua Mountains. No. 101, about one fourth of a mile farther west, occupies 
a still higher spur, being 1,348 meters above sea level, and markiug the second highest point on 
the entire boundary. No. 102, a little more tban a mile west of No. 101, stands upon a third 
high spur at an altitude slightly less than that of No. 100, overlooking a wide broken country 
westward across the Santa Cruz Valley as far as the Patagonia Mountains. 

No. 103 was located about 3^ miles farther west, in the foothills of the Huachucas, a well- 
wooded country much broken by ravines. No. 104, li miles farther on, was located on a plain, 
and near the wagon road connecting the San Pedro Valley with that of the Santa Cruz. No. 105, 
about If miles beyond, stands on a high ridge west of a deep ravine. The latter contains a creek, 
in which flows at times an abundance of fine water. In locating this monument on the 17th of 
July the party encountered one of the severest rainstorms of the season, which flooded the entire 
country and filled the usually dry ravines with rushing torrents. 

Four miles further west No. 106 was built of masonry on the site of old No. 21. Standing upon 
a wide, unobstructed plain, it presents a fine landmark. 

About a kilometer east of this point is the dividing line between Pima and Cochise counties. 
A small, square, sheet-iron shaft, marking the southern extremity of this hue, was found 5.11 







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UNITED STATES AND MEXICAN BOUNDARY. 189 

meters too far south. At the request of tbe county authorities it was moved north to its proper 
position ou the boundary. One and three-fourths miles beyond No. IOC was phiced iron Monument 
No. 107, also ou a grassy plain and near the main wagon road. 

No. 108, old No. 22, was rebuilt of masonry. It stands on the west bank of one of the tributaries 
of the Santa Gruz. This branch, ordinarily dry, was so flooded while the working party was 
i-iimped in the valley that its crossing was several times interrupted. These Hoods would occur 
iilmost instantaneously, and, i)reeeded by a loud roaring noise, a wall of water several feet high 
would suddenly come dashing along, carrying great quantities of drift, including sand, gravel, and 
stones of considerable nuignitude. 

No. 109, an iron monument, located about 2,^ miles west of No. 108, and No. 110, about 2 miles 
still farther west, occupy positions on ridges in a rolling country intersected by shallow ravines, 
which dnring the rainy reason carry the surplus water down from the Ilnachuca Mountains to the 
Santa Cruz Itis^er. 

No. Ill was built from the d(''bris of old No. 23, and occupies a low ridge just west of tlie 
Santa Cruz River, 1 j miles from No. 110. It comunxiuls a fine view of the valley of the Santa 
Cruz to the east, with the Ilnachuca INIountains beyond, and overlooks the plain to the west on 
which is located the small settlement of La Noria, and beyond to the Patagonia Mountains. 

In dry weather the head of the Santa Cruz Kiver is but a short distance north of the boundary. 
The stream here flows south, skirts the southern Jimit of the Tatagonia Mountains, then changes 
its direction to a northern course, and is again crossed by the boundary on the west side of this 
range. In the rainy season numerous ravines in the Huachuca Mountains pour their Hoods into 
the Santa Cruz botii above and below its ordinary head. A long line of wire fen<'e extends from 
the vicinity of La Noria eastward about 20 miles to the Ilnachuca Mountains. It was supposed 
to have been located on the boundary, but was placed several meters north of it. 

About 1^ miles west of No. Ill, and immediately beyond La Noria, was located No. 112 on a 
small hill overlooking the town. No. 113, 3^ miles west of No. 112, stands on the wooded slope 
of the Patagonia Mountains. 

No. 114, jirobably near the site of old No. 24, which could not be found, was located 1:^ miles 
west of No. 113. It is 1,750 meters above sea level, and niarks the highest point of the boundary 
on tlie Patagonia Mountains. This part of the boundary being inaccessible for wagons, they were 
compelled to make a detour south of the range, the work here being done by the aid of pack 
animals. From No. 114 a wide and magnificent view of mountain scenery is afibrded, both toward 
the east and west. 

No. 115 occupies a conspicuous place on a high, dark colored mountain of volcanic rock nearly 
2 miles west of No. 114. This and the preceding monument are of the sectional variety. No. 110, 
also sectional, is about 2^ miles beyond, and near the base of. the Patagonia Mountains. No. 117 
is located on the mesa which descends in a succession of ridges and valleys toward the second 
crossing of the Santa Cruz. It was placed 2| miles west of No. 110. 

No. lis, on the east bank of the Santa Cruz, was erected from the fragments of old No. 25. 
This monument stands at an elevation of 1,132.0 meters above sea level, and marks one of the 
lowest points on the parallel of 31° 20', the elevation being practically the same as that of No. 77, 
at the San Bernardino River. 

The Santa Cruz here flows north, after making a long detour around the southern limit of the 
Patagonia Mountains, and finally reaches the Gila Valley northwest of Tucson. 

No. 119 was i>laced about 3^ miles west of the river on one of the hills west of the valley and 
near a good wagon road leading to Nogales. No. 120 occupies a high, brown mountain li miles 
west of No. 119. This monument marks the highest point of the boundary in the vicinity of 
Nogales, overlooking a wide extent of country in all directions. No. 121 was idaced five-eighths 
of a mile west of No. 120 upon a sharp ridge which looks down upon the town of Nogales at its 
foot. 

No. 122, located on the site of old No. 20, is an iron monument 256.S meters west of No. 121. 
International street, lying wholly upon Mexican soil, passes this monument, the buildings npon 
the American side being so i»laced that their southern walls are exactly on the boundary. The 
old monument had been half covered by one of these buildings, making it necessary to have a 



190 UNITED STATES AND MEXICAN BOUNDARY. 

portiou of the frout wall removed to enable the new monument to be placed in its proper location. 
No. 123 was erected on a low ridge about IJ miles west of No. 122, 

Beyond Nogales the country gradually rises, and on approaching the Pajaritos Mountains 
becomes very rough and broken by deep, precipitous ravines ; wagou transportation was impossible, 
and resort to pack animals was necessary. 

Nos. 124 and 125, the latter sectional, at intervals of nearly 2 miles, were placed on prominent 
ridges of these mountains. No. 126, 2^ miles west of No. 125, occupies one of the highest points 
of the boundary, being 1,022 meters above sea level. The monument, sectional iron, and all the 
materials for its base were carried to the site a number of miles on pack animals. The view from 
this position, especially eastward, is very tine and extensive. 

No. 127, on the site of old No. 27, was built of masonry from the i-emains of that monument. 
It stands on the side of a mountain 231.S meters west of No. 126 and near the bottom of a deep 
valley. It marks the western extremity of the boundary along parallel 31° 20' and the change in 
direction to the azimuth line as determined by the original survey. According to the present 
survey, this point was determined to be 44 miles west of the one hundred and eleventh meridian, 
differing in longitude from the original survey by 4' 34.4". 

Exclusive of No. 53 at its eastern extremity, this section of the boundary is marked by 74 
monuments; 13 are of masonry, located on sites of old monuments; 47 are new solid iron, and 14, 
new sectional iron. The average distance between monuments is 2.3 miles, the maximum being 
6,709.3 meters and the minimum 231.8 meters. 

The whole time consumed in their erection was from the 16th of June until September 19, 
18C3, a period of eighty working days, being an average of six days for each stone monument and 
for each iron monument one and three- tenths days. 

The greatest differences between the United States and Mexican locations occurred at 
Monument No. 80, where the Mexican position fell 1.0 meters south of the American, and at No. 
74, where the Mexican point fell 1.31 meters north of the American. 

3. Azimuth line hetireen the one hundred and eleventh meridian and the Colorado River. 

[2345 miles, 78 monuments.] 

The transfer of the men and transportation of the monument-building party from the meridian 
section of the boundary to Tucson, Ariz., was made early in October, 1893. The force was then 
reorganized and a number of improvements introduced. Monuments, cement, and other supplies 
were hauled from Tucson to the boundary and distributed between the one hundred and eleventh 
meridian and the Pozo Verde Mountains, a distance of about 30 miles. 

From the angle at the one hundred and eleventh meridan westward along the azimuth, the 
boundary passes for a distance of about 25 miles over the Pajaritos Mountains. This range has a 
high elevation (about 1,000 meters above the sea), and is so broken and cut up by deej), precipitous 
canons that the work of erecting monuments was attended with more difficulties than were met 
in the same distance upon any other part of the boundarJ^ 

A supply camp was established near the Warsaw mining mill, from which all work along this 
section was carried on by means of pack animals, the distance by mountain trail to the several 
monuments ranging from a few miles to 22 miles in one instance. 

These preparations were completed during November, and the work of .setting monuments 
began at No. 128 on tiie 22d of that month. 

Monument No. 128, sectional iron, was placed on a high ridge 394 meters westerly from the 
"angle" marked by No. 127. The monument on this ridge marks the highest point of the line 
through these mountains, being 1,002 meters above sea level. It stands near the site of old No. 
XIX, though the latter point was not identified. The pieces for this monument and the cement for 
its base were carried on pack mules 22 miles over very difficult mountain trails. The water 
for concrete was carried 9 miles and the sand 2 miles. 

No. 129, a masonry monument, was built of dressed stone on the site of old No. XVIII. It 
occupies a high mountain ridge 34 miles from No. 128. The sand, water, and cement for this work 
were packed sevex-al miles. 




Erecting Monument No. ] 
ON Cerro de la Lesna. 



ErECCION del MONUIIENTO No. 

SN KL Cekko de la Eesna. 



UNITED STATES AND MEXICAN BOUNDARY. 191 

No. 130, a sectional iron monumeut, was located ou a high iiiomitaiu 2^ miles beyond No. 129. 
Tbe monument in sections, the sand and water, were carried ou pack mules 10 miles. Its position 
commands a fine view of tbe surrounding mountains and canons. 

No. 131, also sectional, was carried 8 miles over mountain trails and placed on a high ridge 
3i miles farther on. 

No. 132 was located 3^ miles beyond on another high hill, and required the use of pack animals, 
the monumeut in sections being carried about G miles. 

No. 133 was placed li miles beyond No. 132; another sectional monument requiring the use 
of pack animals. 

No. 134, about 2 miles farther on, and No. 135, 3^ miles beyond the latter, are of solid iron, 
and occupy positions on a less broken part of the line, accessible for the monumeut wagon. 

No. 130, built of masonry, and located on the site of old No. XVII, li miles beyond No. 135, 
stands upon the summit of the Fresnal Mountain, a high, rugged landmark which overlooks a 
large extent of sui-rounding country. This monument was well constructed of dressed stone 
found at the locality, but cement, water, and sand were carried several miles on pack mules. 

No. 137, also a masonry monumeut, occupies the site of old No. XVI on a high, rocky hill, 25 
miles west of No. 130. 

Nos. 138, 139, and 140, solid iron monuments, mark the line over the rolling country between 
the Fresnal Mountain and the Pozo Verde range. They were placed ou hills at intervals of about 
2.i miles. Near the latter is the thriving ranch known as La Osa. 

No. 141 occupies a commauding position ou the crest of the Pozo Verde Mountains 1^ miles 
west of No. 140. This is a masonry monumeut built on the site of old No. XV. The difficulties 
here were such that the cement and water were carried by pack mules 2i miles. A magnificent 
view both east and west is afforded from this location. 

Nos. 142, 143, 144, and 145 are solid iron monuments, marking the line at intervals of about 3^ 
miles across the mesa country lying between the Pozo Verde and the Moreuo mountains. This 
is an arid region, though occasional rains occur, and considerable grass is found on some of the 
plains, which, with the aid of a few pumping wells, supports a number of herds of horses and 
cattle. 

No. 146, occupying the site of old No. XIV and 4 miles west of No. 145, marks the highest point 
where the boundary crosses the Moreno Mountains, the "Cerro dela Union" of the P^mory survey. 
It is a masonry monumeut, and on account of the difficulties of the situation jiack animals were 
necessary in conveying the material to the site. 

No. 147, a solid iron monument, placed 4i miles west of No. 14G; No. 148, about 2i miles beyond 
upon the same general declivity, and No. 149, nearly 3 miles farther on, mark the boundary 
between old Nos. XIV and XIII. 

No. 15(», on the site of old No. XIII and built of masonry, is 2i miles beyond No. 149. It stands 
near the crossing of the main road and also near a high, i)recipitous rock. It was well built of 
cut stone and provided with the usual inscriptions. The Indian village Cobota is located iu this 
vicinity. 

No. 151, 2^ miles beyond No. 150, and No. 152, 3^ miles still farther west, are solid iron 
monuments, marking slightly elevated points in the open and nearly level couutry. 

No. 153, 2,3 miles west of No. 152, occupies the most remarkable position on the entire bound- 
ary. The line iu crossing the Cerro de la Lesna rises abruptly from the plain below, a distance of 
about 500 feet, the upper 100 feet being a .sheer precipice ou both sides. To reach the summit of 
this ridge required a specially skillful and athletic climber to carry a rope, by means of which 
others were enabled to ascend and perform the work of erecting th's monumeut. It is of the sec- 
tional iron type, the pieces and other materials being carried as far as possible ou pack animals, 
and then hoisted by hand, with the aid of ropes, to the summit. The knife-edge crest was blasted 
off to give sufficient width for the ba.se of the monument, which was then bolted to the solid rock. 
The erection of this momimeut i^roved to be the most difficult upon the entire boundary, requiring 
four days of excessive labor. 

West of the Cerro de la Lesna a sandy, rolling plain extends to the Nariz Mountain, a 
distance of 18 miles, across which the boundary is marked by iron monuments Nos. 154, 155, 150, 
157, and 158, at intervals varying from 2^ to SJ miles. 



192 UNITED STATES AND MEXICAN BOUNDARY. 

No. 150, 2g miles farther on, marks the crossing of tlie bountlary over a rough, higli, blaclc lava 
ridge, the outlying spur of the Nariz Mountain. The truck wagon could not reach this site, and 
a sectional monument was placed here, the pieces being carried by pack train. 

No. ICO is a monument of cut stone marking the point where the line crosses the summit of 
the Nariz Mountain and built on the site of old No. XII. Its locatioji is 2h miles west of No. 159 
and its elevation about 1,000 feet above the valley on either side. It overlooks a wide extent of 
country to the eastward and the narrow valley to the west. 

No. 1(51, an iron monument, stands in this ^•alley, the Santa Rosa, 1\ miles beyond No. 160. 
Old No. XI is supposed to have been located near this point, but was not found. 

No. 1(52, a masonry monument on the site of old No. X, marks the crossing of the boundaiy 
over the Santa Rosa Mountains 3;^ miles beyond No. IGl. These two ranges are about 5 miles 
apart where the boundary crosses. 

The (ionstruction of this monument was attended with much difficulty, pack animals being 
necessary for transportation up the steep mountain slopes, and considerable work was expended 
upon the trail to make it passable for mules. 

No. 1(53, a sectional iron monument, was placed on a sliarp lava spur of the Nariz IJ miles 
west of No. 1C2. Its erection was also quite diflBcult. 

The country beyond this point for a distance of about 13 miles is comparatively level, the 
most serious difficulty encountered being the lack of water, which had to be carried long distances. 

Along this section of the line were erected iron monuments Nos. 104, 105, 16C, and 167, at 
intervals of about 3 miles. 

No. 168 occupies the site of old No. IX. It was built of masonry and stands upon a high hill 
1^ miles beyond No. 167, and is near tlie Mexican settlement of Sonoyta. 

Between this point and old Monument No. VI, a distance of 20 miles, the country is a rolling, 
hilly mesa, over which the boundary is marked by 6 iron monuments, Nos. 169, 170, 171,-172, 173, 
and 174, the intervals between them varying from 2 to 3^ miles. No. 172 was located at the old 
village of Quitobaquita, and near and south of the valuable springs of tiiat name. Old Monuments 
Nos. VII and VIII had been located in this vicinity, but no trace of them could be found. 

No. 175, a masonry monument, was built on the site of old No. VI, upon a high, rocky bill, about 
9 miles west of the springs. It overlooks a large area of adjoining country to the eastward. 

No. 176 was placed 2S miles beyond on a narrow ridge extending southward from the Quitoba- 
quita Mountains. 

No. 177 was located upon the Hat mesa 3^ miles farther on. 

No. 178, 4f miles beyond 177, was placed on a high, rough, lava liill, rendering it necessary to 
carry by hand the monument from the base of the hill to its position. 

No. 179, about 3 miles farther west, was placed upon another sharp hill, though less difficult 
than the preceding. 

Nos. 180, 181 ,182, and 183 continued the marking of the line over the Tule Desert to tlie base 
of the Tule Mountains. They were usually placed on lava ridges at intervals of about 4^ miles. 
The locations for Nos. 182 and 183 were such that the monuments were of necessity carried by 
liand short distances to their positions. 

No. 184, a sectional iron monument, was placed on a very high mountain of the Tule group at 
a distance of 2§ miles from No. 183. It overlooks a vast extent of country eastward, the immediate 
neighborhood being a succession of rugged mountains, divided by deep, precipitous canons. 
The steep, rocky sides of this mountain would not admit of even pack transportation, the pieces 
of the monument being carried by hand about 1^ miles. 

On a still higher and more rugged mountain 2^ miles beyond was located No. 185. The work 
here was still more difficult. Pack animals were used in carrying the sections of the monument 
part way up the slope and the work completed by hand. This monument commands a magnificent 
view of rough and rugged mountain peaks rising in needle like sharpness and separated by 
canons whose sides are often vertical precipices. 

No. 186 was placed where the boundary crosses the highest ridge of the Tule Mountains. It 
is 2ii miles west of the preceding, and like the other its erection was attended with severe labor, 
requiring hand transportation a part of the way. 



UNITED STATES AND MEXICAN BOUNDARY. 193 

No. 187, on the most westerly ridge of the Tules, 2.V miles farther on, was erected also with 
great labor, as this ridge, though not as high as the others, was extremely rough. A solid monu- 
ment had been provided for this point, and its transportation to the site was a difficult problem, 
effected by using one pair of the wheels of the track wagon and trailing the monument upon a 
timber lashed beneath it. 

No. 188 was placed about midway of the valley beyond and 45 miles west of No. 187, 

No. 189, sectional, about 4 miles beyond No. 188, marks the crossing of the Lechnguilla 
Mountains, a high, rocky position which was barely accessible by pack mules. 

Two and one-fourth miles distant from No. 180, upon a small hill, was located No. 190, near the 
foot of tlie Tinajas Altas Mountains. This range is one of the roughest and most precipitous 
encountered on the entire boundary, though the line in crossing it reaches an altitude above the 
sea of only G44 meters. The contrast betweeu the valleys and steep mountains, whose sides are 
frequently vertical for many hundred feet, is more strongly marked than elsewhere along the 
boundary. The almost total absence of vegetation, sharp, rugged rocks only being visible, adds 
materially to the wild and desolate effect. 

No. 191 was placed '2 miles beyond No. 190, and marks the point where the boundary reaches 
its highest elevation in crossing these mountains. In the immediate vicinity are many other high 
ridges, with intervening chasms several hundred feet in deptli. The summits of these ridges are 
so narrow that men found great difticulty in retaining their positions while at work upon the survey. 
The monuments upon these rocky mountain tops were all of the sectional kind, and were bolted 
to the solid rock after the surface had been suitably leveled by blasting. 

No. 193 was iilaceil on a high ridge about 2 miles west of No. 191 , and marks the last mountain 
point east of the Yuma Desert. This and tlie prieceding were of the sectional variety. 

From the foot of these mountains the desert has a gradual and nearly uniform descent to the 
Colorado River of about 250 meters in 70 kilometers. This gradual descent is only broken at one 
place, about midway of the slope, by a range of sand dunes bordei'ed on the southwest, for a 
distance of about 1 mile, by a ridge of volcanic rock. The boundary crosses the northern end of 
this ridge, at which jjoint No. 198 was placed and occupies a conspicuous position. The monu- 
ments on this desert as far as No. 204 are all of solid iron, resting on concrete bases. They are 
niimbered from 193 to 203, inclusive, and were placed at intervals generally of about 6,000 
meters. 

No. 204, marking the westerly limit of the desert mesa and overlooking the Colorado bottom, 
is old No. II of the original line, repaired and provided with a new concrete foundation. The old 
monument was made of cast-iron plates resting upon a defective foundation, which had almost 
disappeared, permitting the structure to settle and become unstable. It was taken down, a 
heavy concrete foundation built on the exact site, and the monument carefully rebuilt, painted 
white, and provided with the new inscri^jtion plates. It now presents a very fine appearance. 

The last monument on this section of the boundary is No. 205, which was placed in the river 
bottom 3,000 meters west of No. 201 and near the bank of the Colorado, in a heavy growth of 
cottonwoods and willows. No. I of the original survey was located near this point, but all trace 
of it has disappeared. 

Of the 78 monuments now marking this section of the boundai-y, 53 are new iron, cast whole, 
14 are new iron, in sections, 1 old iron, sectional, rebuilt, and 10 are of masonry upon the sites 
of old monuments. The average distance between monuments is 3 miles, the maximum being 
7,898 meters and the minimum 393.5 meters. 

The greatest difference between the United States and Mexican locations occurred at Monu- 
ment No. 191, on the summit of the Tinajas Altas, being 2.04 meters, the Mexican position falling 
north of the United States. This difference is also the greatest on the entire boundary. In 
many cases the difference was inappreciable, while frequently the Mexican point fell south of the 
American. 

Monument work on this section of the boundary commenced November 22, 1893, and 
continued until March 14, a period of ninety-four working days, the average time for erecting 
each iron monument being one and one-fourth days and for each of masonry three days. 



194 UNITED STATES AND MEXICAN BOUNDARY. 

The party as organized for this section was necessarily larger than heretofore, as the work 
was remote from railway transportation and required the maintenance of a special camp near the 
working party to aflbrd the necessary supplies. These were at first hauled from Tucson, 70 to 
150 miles, afterwards from Gila Bend, Adonde, and Yuma, as the work progressed westward. 

The organization was as follows: Col. J. W. Barlow, commissioner, in general charge until 
disabled by an accident in December; Mr. B. A. Wood, assistant engineer, in charge of location, 
and in general charge after December ; Mr. D. II. Payne, overseer and photographer; Mr. J. T. 
Amos, quartermaster and property clerk; Mr. M. E. Cunningham, wagon master; 1 rodman, 1 
blacksmith, 1 stone mason, 9 teamsters, 9 laborers, 2 cooks, and 2 helpers, 2 spring wagons, 
1 buckboard, 3 water wagons, 5 baggage wagons, 1 truck wagon, 5 horses, and 30 mules. 

4. The azimuth line from the Colorado River to the Pacific Ocean. 

[141 miles, 53 monnmeats.l 

On reaching the Colorado Kiver the monument party was reorganized and the force of men 
and teams reduced. This was possible by reason of better facilities for obtaining supplies, a 
special supply camp being no longer necessary. 

After a short delay at Yuma the work on the southern California line was taken up, with the 
following organization: E. L. Ingram, assistant engineer, in charge; 1). R. Payne, overseer and 
photographer; M. E. Cunningham, wagon master; 1 cook, 1 waiter, 2 packers, 3 teamsters, 1 
blacksmith, 5 laborers, 2 baggage wagons, 2 water-tank wagons, 1 truck wagon, 1 spring wagon, 
1 buckboard, 26 mules, 3 horses. 

From the western extremity of the Arizona line the boundary follows the channel of the 
Colorado liiver northward about 24 miles to the boundary of California. This being a part of the 
water boundary between the United States and Mexico, the adjustment of which has been provided 
for under another convention, no monuments have been erected in connection therewith. This 
water boundary is held to extend to the point where the boundary between California and Mexico 
intersects the channel of this river, which is about miles below the mouth of the Gila. 

From this point the work of marking the boundary westward to the Pacific was taken up. 
Operations began on the 20th of March, 1894, by the erection of No. 200. This is an iron monu- 
ment, and was placed 229 meters west of the center of the river channel, in a growth of willow and 
Cottonwood trees. 

No. 207, on the edge of the mesa, 810 meters from No. 200, and overlooking the river valley, 
was built of masonry. It stands at the south foot of Pilot Knob Mountain and replaces old 
No. VI, which was originally of cast iron but had been destroyed. 

No. 208, an iron monument, was placed 2 miles beyond on the same mesa and near a line of 
heavy sand hills. 

No. 209, about 4 miles farther west, stands among sand hills but upon firm ground. 

No. 210, about 4;^ miles beyond No. 209, was placed on a soft, sandy plain which proved to be 
unstable, the wind cutting the sand from one side of the foundation and causing the monument to 
topple over. This unsafe condition was afterwards remedied by sinking the base lower and secur- 
ing it by driving 8 iron pipes 12 feet into the ground, 2 at each corner of the base, and held in 
place at top by connecting iron bars. Should the sand drift away hereafter the monument would 
probably remain upright and settle vertically. 

Through this part of the desert, composed of sand which moves in wave like drifts, the monu- 
ments, G in number, were each provided with a hollow iron mast, 15 feet long, attached to the side 
of the monument near the top. These masts will probably remain visible in case the monuments 
shall become buried in sand drifts. 

From the Colorado River westward the boundary, for a distance of about 10 miles, passes 
over a desert region composed of sand ridges almost totally devoid of vegetation. Adjacent and 
south of the line the valley of Saltou Klver, frequently overflowed by the Colorado, and in which 
lies the old Yuma and San Diego wagon road, presents a marked contrast to this arid waste, 
having at times many pools of fair water left from the overflow of the Colorado River and an 
abundant growth of mesquite and other vegetation. 



UNITED STATES AND MEXICAN BOUNDARY. 195 

Monuments Nos. 211, 212, 213, 211, 215, 216, and 217 continue the marking of tlie boundary 
over this desert at intervals of about 3:^ miles. 

No. 218, 3^ miles beyond 217, marks a point in the Salton A'alley, which is here crossed by the 
boundary and trends in a northwest direction toward the Salton Lake. 

No. 219, 3 miles farther on, is located in the same valley. 

No. 220, 3j| miles beyond and just east of New Eiver, is old No. V, repaired and placed upon 
a new concrete foundation. 

No. 221 stands west of New River. It is old No. IV, la miles beyond No. 220, also repaired 
and given a new foundation of concrete. These foundations were made 3 feet square and 4 feet 
high, with 2 feet showing above the ground, and upon them were placed the usual iron inscription 
plates. 

No. 222 marks a point in the New Kiver Valley about 4i miles beyond No. 221, and No. 223 was 
placed in the same valley 3^ miles farther west. 

The last four monuments mark the lowest depression on the entire boundary. No. 220 at the 
sea level, the others below it. No. 223 is 4.37 meters below sea level. 

The vegetation here is similar to that in the Salton Valley and indicates a line, rich soil, 
capable under irrigation of yielding abundant crops of grain and all the semitropical fruits. A 
comprehensive plan for bringing the Colorado water into this region, by means of a canal tapping 
the river about 12 miles above Yuma, has been under consideration for some time, extensive 
preliminary and locating surveys having been carried on during the winter of 1893-94. 

No. 224, 4 miles beyond No. 223, marks the crossing of a considerable ridge, one of the spurs 
of Signal Mountain, a high detached peak just south of the line. 

No. 225, about 1 mile beyond, marks a second spur of this mountain. 

Nos. 226, 227, and 22S fall on the arid desert which now gradually ascends toward the Coast 
Range. These monuments were placed at intervals of about 3 miles. This region is as desolate 
and uninviting as can well be imagined; devoid of water, almost of vegetation, broken by sharp, 
rocky canons, it has been the scene of many tragedies. The impression has prevailed that the 
l^recious metals are somewhere hidden away in the recesses of these gorges, and several jiros- 
pectors, lured by the hope of liudiug rich deposits, have ventured too far from supplies and left 
their bones as witnesses of their rashness. 

No. 229 marks the crossing of a high, detached ridge near the Coast Range. A sectional 
monument was packed to the point with great ditticulty after expending considerable labor in 
preparing a trail up the rough, volcanic slope of the mountain. It stands 3 miles west of No. 228. 

No. 230 was placed upon the crest of a still higher ridge, a part of the Coast Range proper, 
and 43 miles beyond the preceding, a sharp, rocky valley intervening. Much ditticulty was here 
encountered. The preparation of a trail for the pack mules carrying the sections of the monument 
was necessary to reach a point within 100 meters of the location. Beyond this the mules could 
not proceed, and the pieces were thence carried by hand. The monument was bolted to the solid 
rock. 

No. 231, sectional, about 4.^ miles beyond, was placed upon the summit of the range, its 
elevation being 1,371 meters above sea level. The approach to this monument is by way of the 
Mountain Spring Caiion, several miles to the north, through which i)asses the old Yuma and San 
Diego wagon road. When used by the overland stage line the road was kept in fine condition, 
but neglect on the i)art of the authorities and the earthquakes aiul storms of recent years had left 
it so bad that travel was attended with great labor and ditticulty. The monument stands about 
250 meters back from the extreme verge of the cliflf, which here rises, an almost vertical wall of 
rock, from the rough, broken foothills below. The rim of this clift' marks a sudden and wonderful 
change in the character of the country. East of this line the great desert of the Colorado 
extends to the limit of vision dry and arid, with volcanic ridges and gorges in the foreground. 
Utterly destitute of vegetation, it is a region apparently without life. Westward the mountains 
are clothed in verdure; trees, l)ushes, and grass are everywhere; animals abound in great variety. 
The moisture from the ocean here prevails and is condensed into refreshing showers. To the east 



196 UNITED STATES AND MEXICAN BOUNDARY. 

the hot air of the desert rises and forms a barrier through whicli mists sekhim penetrate, being 
either rolled back by the desert winds or dissipated in the upper atmosphere. 

No. 232, 3 miles west of No. 231. stands in a saddle of a high mountain ridge, very rough, but 
reached with the monument track. Its site overlooks the beautiful Jacumba Valley to the west. 

No. 233, nearly 3 miles farther west, stands on a low ridge three-quarters of a mile southwest 
of the Jacumba sul|)hur spring and at the foot of a very large bowlder, which readers it invisible 
from the road 300 meters to the north. 

No. 234, 2.V miles beyond, was located on the south wall of Jacumba Oauon and near its top 
In placing this monument in position a long detour was necessary to reach the summit of the 
mountain with the pack train. The pieces of the monument by the aid of ropes were lowered down 
vertical cliffs to the site selected and the base bolted to solid rock. 

No. 235, a sectional monument about 3 miles west, was bolted to the top of a huge bowlder 
upon an elevated ridge. This mountain region is much broken by hills and ridges, many of them 
being mountains rising several hundred meters above the valleys. The latter are frequently quite 
broad, att'ording line water and excellent grazing. Others are but narrow, deep canons with 
precipitous sides. 

Nos. 236, 237, 23S, 230, and 240 were placed on hills at distances apart varying from I'l to 2i 
miles. No. 240 being just east of the main road leading south from Campo, the latter being 1^ miles 
north of the line. 

No. 241, a sectional monument, was placed on a high rocky ridge about 1 mile beyond 240 
and west of a branch road leading to the Tijuana Valley. 

No. 242, sectional, also upon a high ridge, was placed 3 miles west of No. 241, and No. 243, 3;^ 
miles farther west, upon the north slope of a conspicuous conical hill. 

No. 244, about 1 mile west of No. 243, marks a point near the road leading to Potrero, 2^ miles 
north. 

No. 245 was placed on a low ridge in a valley near the east foot of Mount. Tecate, and 2i 
miles beyond No. 244. A portion of this valley is under cultivation, containing several improved 
ranches. Just west of this monument rises the bold scarp of Mount. Tecate, steep and rugged, 
nearly 500 meters above the valley up which in a zigzag course the pack train carried Monument 
No. 240 in sections, where it was placed about 2 miles distant from 245. 

The crest of this mountain is a horseshoe ridge opening to the south, the two branches where 
the line crosses being about one half mile apart. Upon the second of these No. 247, also a sectional 
monument, was placed. The pieces of this were carried up the mountain slope from the west side, 
the deep and rocky intervening canon making it impracticable to cross directly from the east. 

These monuments occupy positions from which the most magnificent scope of mountain 
country upon the whole boundary is visible. The Coast Eange as far as the eye can reach is 
spread out to the east, south, and specially to the west, beyond which the Pacific Ocean is seen 
rolling its surf upon the beach, about 25 miles distant. 

No. 248, also a sectional monument, was placed upon a sharp ridge west of Tecate Mountain, 
and 2^ miles beyond No. 247. At the foot of this ridge the Tecate Eiver flows through a narrow 
valley in a westerly direction, and, joining the Cottonwood about 2 miles beyond, the united streams 
form the Tijuana River. 

No. 249 was placed on a low ridge in the Tijuana Valley one-half mile below the junction of 
Cottonwood and Tecate rivers. 

No. 250, sectional iron, on a high ridge in the latter valley, was located Ig miles beyond No. 
249, overlooking the valley in both directions. 

No. 251, a sectional monument, stands on the south slope of Otay Mountain, near the summit, 
and commands a fine view of the country west to the Pacific. It was located 4 miles west of 
No. 250. 

No. 252, 21 miles farther west, is a masonry monument, built on the site of old No. III. It 
stands on the Otay mesa and near the foot of Otay Mountain. 







1 

i 
i 

1 


" f'^ '''^:- ' 





UNITED STATES AND MEXICAN BOUNDAKY. 



197 



No. 253, about 3i miles farther west, aud 254, about 2J miles beyoud, continue tlie boundary 
across the mesa to the Tijuana Valley. 

No. 255, in the Tijuana Valley, occupies a low bench of the plateau north of the i-iver, aud l.J 
miles west of No. 254. This is a special monument, built of granite, of the same size as the other 
masonry monuments, but constructed with reference to the importance of the site. It is composed 
of but three pieces, resting on a foundation of concrete. The joints of the stones are all carefully 
cut; the exterior surfaces, with the exception of i panels on the respective sides and the faces of 
the pyramid at top, are left rough. The 4 panels bearing the inscriptions are polished, and tlie 
corners of the monument line cut work. The whole effect is very satisfactory. Follon-iug are the 
inscriptions on the 4 panels: 



On the north: 


Un the south: 


071 the ea$t: 


On the west: 


Boundary 


Limite 


255 


255 


of the 


dela 


Seccion Jlexicana 


United States 


United States 


Republica 


dela 


Commissioners: 


Treaty of 


Mesic.ana 


Comisiou Internacional 


Col. J.W. Barlow, 


1853 


Tratado de 1853 


deLimites: 


Corps of Engineers. 


Re-established 


Kest.ablecido 


Jacobo Blanco, 


Lieut. D.D.Gaillard, 


by conveutions of 


por 


lugeniero ou Jefe. 


Corps of Engineers. 


1882-1889. 


Couveuciones de 


Valentin Gama, 


Asst.A. T. Mosman, 




1882-1889. 


Adjunto Astroiiomo. 


Coast and Geodetic Survey 


The destruction or 




Caspar M. Ceballos, 




displacement of this 


La destmccion 


Cai)taiu de E. M. E., 




monument is a ' 


o dislocacion de 


Ingeniero Auxiliar 




misdemeanor 


esto monnmeuto es 






punishable by the 


un delito punible 






United States or 


por Mexico o los 






Mexico. 


Estados Uuidos. 







To protect this monument from injury by toui'ists a steel picket fence 7 feet high, inclosing 
an area 12 feet square, was built around it; the posts were embedded in granite blocks, and the 
interior space covered with a paving of artificial stone. 

It was intended to perpetuate the site of old No. II, which was located at the crossing of the 
Tijuana River by the main highway leading to Mexico, and where the Mexican village of Tijuana 
has since been built. A monument of which the present 255 is a dupUcate was erected at that 
point, but during the heavy Hoods of January, 1895, it was entirely destroyed aud its fragments 
buried beyond recovery in the quicksands of the river. The bed of the stream was so changed 
that the site of old No. II lies in its mid channel. As the difficulty and expense of preparing a 
new foundation for a monument at the old point would be very great, and there being no real 
necessity for so doing, it was agreed between the engineers in chief to abandon the position and 
erect another monument, a duplicate of the one lost, on solid ground north of the river, and about 
1,000 meters east of the old site. The village of Tijuana, badly damaged by the last flood aud 
even more seriously injured by that of 1890, will now probably move many of its buildings to the 
vicinity of the new monument, where the customhouses of both countries are to be located, anil 
where the ground is high and entirely secure from future floods. 

The boundary here crosses obliquely the Tijuana Valley and reaches the mesa again about 2i 
miles west upon the crest of which No. 256 was located, a little more than 3 miles beyond No. 255. 

No. 257, beyond two sharp ravines and upon a high ridge of the mesa, li miles beyond No. 
256, commands a fine view of tlie ocean and the city and harbor of San Diego. 

No. 258 is the old initial monument of the original survey. It had become so mutilated by 
visitors that its outlines were nearly destroyed and its inscriptions partly obliterated. Chippings 
from the top and corners had been carried away, and so much of the base had been removed that 
the monument was becoming insecure on its foundation. It was decided to have it entirely 
remodeled. This work was done in San Diego, the monument being taken to the marble yard of 
Messrs. Simpson & Pirnie, where it was recut; its size reduced a few inches in all dimensions; it 



198 



UNITED STATES AND MEXICAN BOUNDARY. 



was then repolished aud the original iiiscriptious restored as far as 
Including certain additions these inscriptions are now as follows: 



deemed consistent. 



On the north: 


On the south: 


On. ih, 


west: 


Boundary 


Liniite 


Initial point of 


Punto inieial del 


of till! 


dela 


Boundary between 


Limite entre Mexico 


United States. 


Republica 


the United States and 


y los Estados Unidos, 




Mexicana. 


Mexico, established 


tijado por la 


The destruction 


La destrucoiou 


by the Joint Commission 


Comisiou Unida 


or displacement 


dislocacion 


10 October, A. D. 1849 


10 de Octubre A. D. 1849 


of this monumeut 


de este monumento 


Agreeably to the 


Segun el Tratado 




.■s un delito 


Treaty dated at the 


Concluida en la 


punishable by the 


punible por 


City of Guadalupe 


Ciudad de Guadalupe 


United States 


Mexico o los 


Hidalgo, 


Hidalgo el 2 de 


or Mexico. 


Estados Uiiidos. 


February 2, A. D. 1848. 


Febrero A. D. 1848. 






.John B. Weller, 


Pedro Garcia Conde, 


On the cast: 


U. S. Commissioner. 


Comisionado Mexicano. 


258 


Andrew B. Gray, 


Jose Salazar Ylarregui, 


Keconstruido 


Reconstructed 


U. S. Surveyor. 


Agrimensor Mexicano. 


Asosto di' 1894, 


August, 1894, 






porla 


by the 






Comisiou Internacional 


International 






de Limites 


Boundary Commission 






creada por los 


created by the 






Convencioncs de 


Conventions of 






1882 y 1889. 


1882 and 1889. 







lud Don .Jose Salazar 



Marble not being readily obtainable, a granite base to replace that of marble destroyed by 
visitors was also provided. It was then returned to its site and reerected upon a new concrete 
foundation. 

Two documents, one in English and one in Spanish, recording the names of the Commissioners 
and engineers employed on the present survey were engrossed upon iiarchment, encased in a 
copper tube, and embedded in the foundation. Following is a copy of the English document: 

This paper was deposited in the foundation of Monument No. 2,")8, October 3rd, 1894. 

This monnment was originally erected by Wm. H. Emory, United States Commissionei 
y Larrcgui, Mexican Commissioner, on October 10th, 1849. 

This monument was recut and re-erected under the direction of the International Boundary Conn 
United States and Mexico, which has re-established the boundary line between the United States and Mexico, from 
the Eio Grande to the Pacific Ocean, under the conventions of .July 29th, 1882, and February 18th, 1889, by the 
erection of 258 monuments under the Administrations of Presidents Benjamin Harrison and Grover Cleveland, 
.Tames G. Blaine and Walter Q. Gresbam their respectixe Secretaries of State. 

United States Commissioners: J. W. Barlow, lieutenant colonel of Engineers, U. S. Army; D. D. Gaillard, Ist 
lieutenant of engineers, U. S. Army; A. T. Mosmau, Assistant, U. S. Coast and Geodetic Survey. 

Engineers employed on the survey: John F. Hayford, assistant astronomer; .lohn L. Van Ornum, assistant 
engineer; Edward L. Ingram, assistant engineer; Bernard A. Wood, assistant engineer; and L. Seward Terry, 
Secretary of U. S. Commission. 

A steel i)icket fence to protect the monument from injury, and an interior jjavement were 
|)rovided, as at No. 255. The pickets of these fences curve in at the top, making access to the 
inclosure extremely difficult. 

The erection of this monument completed the marking of the southern California line and 
the entire bonndary between the Kio Grande and the Pacific Ocean. 

Of the 53 monuments on this section of the boundary 35 are of iron, cast solid; 12 are iron, 
sectional; 2 old sectional iron, repaired; 2 of masonry built on old sites; 1 granite; 1 marble, 
recut from old initial monument. 

The average distance between monuments is 2.7 miles; the maximum 7,533 meters; the 
minimum 809 meters. 

The work began on March 20 and continued until June 30, 189i, during a period of eighty- 
eight working days, in which the monuments, except the 2 built by contract, were erected; the 
average time per monument being about one and eight tenths days. 



INTERNATIONAL BOUJNDARY SURVEY 

UNITED STATES AND MEXICO 



k. 



T 



|eG"-i- ^4 — Lo"--|c — ^e'N 



NOTE. 

ThicTmess of Metal jf " 
Bolts 2!l"l)etweeiiTVasliers 
aiLcL 1" Diameter. 
Nuts 2 "Toxmd, 1^ Hexagon- 
He aa.. "Washers 6"DiaiiL.lry- 
i "iMck 



3.0" 

ELEVATION 




i — 


S'.O" - 















'f 




H 






^®""' 


CI 


®- 




-s 




H. 








i 




1 



DESIGN FOR IRON MONUMENTS 

ADOFTED NOVEMBER 1891 
SCALE -5-"= I'O" 





ELEVATION AND SECTION 



ELEVATION AND SECTION 





DESIGNS FOR SECTION^M. IRON ^MONUMENTS 



SCALE. 4 = I'O" 



INTERNATIONAL BOUNDARY SURVEY 

UNITED STATES AND :MEXIC0 




DESIGN TOR STONE MONUMENTS 



ADOPTED JUNE 3 ■"'^1893 

SCALE y=\'.0" 



UNITED STATES AND MEXICAN BOUNDARY. 199 

The greatest difFerence between the United States and Mexican offsets, 1.48 meters, occurred 
at Monument No. 211, the Mexican point being north of the American. 

The aggregate length of tlie several sections of the boundary now marked by monuments is 
675 miles, the whole number of monuments being 258. The average distance apart is about 2.G 
miles, and in no case has the limit of 8,000 meters been exceeded. 

Summart/. 

Number of original monumeutB idiutitied and repaired or replaced 43 

Niiral)er of new points established and iimrked with iron monnnients 215 

Number of new solid iron monuments erected on new sites ]7n 

Number of new sectional iron monuments erected on new sites 40 

Number of new solid iron monuments erected on old sites 1 

Number of old sectional iron monumonts repaired 3 

Number of old masonry uionumeuts repaircil 5 

Number of old masonry mouuuients rebuilt 32 

Number of new granite monuments built 1 

Number of old marble monuments rebuilt 1 

CHAPTER VIII. 

PHOTOGRAPHY, BIOLOGY, AND FINANCIAL STATEMENT. 
rilOTOGRAPHY. 

The commission decided, as a part of its original plan of operations, to employ a photographer 
and to provide him with an outfit for tailing such views along the line as would be useful in 
illustrating the character of the country, and also as an adjunct to the maps in fixing the locations 
of new monuments. 

Mr. J. H. Wright, of Nashville, Tenn,, was at first employed. He accompanied the main 
camp of the survey party along the parallel of 31° 47' and photographed the old monuments upon 
this part of the boundary, but his work did not prove satisfactory and he was discharged. 

Mr. M. J. Lemmon, of El Paso, Tex., was appointed in his place, continuing with the expedi- 
tion as far as San Bernardino, on parallel 31° 20', -when his services were also discontinued. 

In August, 1892, Mr. D. E. Payne, of Albuquerque, N. Mex., was engaged to succeed Mr. 
Lemmon. Mr. Payne proved to be an experienced and skillful photographer, and was continued 
in service until the completion of the photographic work in June, 1894. 

The camera was of the portable type, with 8 by 10 inch glass plates, and was furnished with 
an excellent lens. The necessary plate-holders, printing frames, baths, a supply of chemicals, and 
a developing tent were also provided. The outfit was usually tranported in one of the spring 
wagons, but on portions of the line where wagons were impracticable Mr. I'ayne managed to 
carry the camera and other necessary articles on horse or mule back. The trails were frequently 
rough and sometimes dangerous, but happily no serious accident ever occurred to the camera or 
its belougings. 

The plates were developed as frequently as practicable, and test prints made as a check upon 
the character of the work. 

It was the intention to obtain one or more views of the old monuments to illustrate their 
condition at tlie time of the survey, and at least two of all the new monuments after their erection, 
as a help to the topography in identifying their locations. Where possible the monuments were 
photographed against a distinctive mountain or hill in the immediate vicinity. 

The work done by Mr. Payne's jiredecessors not being entirely satisfactory, it was fortunate 
that he joined the monument party in El Paso at the beginning of its operations, thus permitting 
him to go over the entire line with this party and supply any previous deficiencies. 

Photographs of 39 of the old monuments were obtained, which exhibit types of the previous 
structures employed, the rude heaps of loose stones on parallel 31° 20' and the Souora line, and the 
several cut-stoue, masonry, and iron shafts which were found at other jjoiuts. 



200 



UNITED STATE!? AND MEXICAN BOUNDARY. 



The monuments, new and repaired, on tbe entire line, 258 in number, were photographed, one 
or more views being taken both by the American and Mexican photographers. These views will be 
of assistance in recovering the positions of monuments in case of their destruction. 

Views characteristic of the country were taken iu addition to those of the monuments. These 
show specially interesting natural scenery, such as settlements, public buildings iu the vicinity of 
the boundary, also camps, ranches, etc. 

At the close of the field work in June, 1S94, the photographer was engaged at San Diego until 
December in preparing four copies of each view, Avhich were mounted iu albums and, with the 
negatives, transmitted to the Department. 

When the commission assembled iu Wasliiugtou, in October, 1895, the question of obtaining 
plates from which to print copies of the photographs for publication with the report was cousid- 
ered. After quite an extensive investigation it was finally determined to adopt the method known 
as half-tone engraving, which, on account of its cheapness and accuracy, promised the most 
satisfactory results. 

Accordingly a contract was entered into with the F. Gutekunst Company, of Philadelphia, 
for furnishing, on account of the joint commission, 300 half-tone plates of selected views. These 
selections comprise 200 views of new monuments, 8 views of old monuments, and 32 special 
subjects, as specified in the following list: 



Vieics selected hy the engineers in chief for illmtratUui Ihe joint report of the International Boundarij Commission, United 

States and Mejiico. 



No. 17.. 
No. 18.. 
No. 19., 



No. 20.. 
No. 21.. 
No. 23.. 
No. 23., 
No. 24., 



No. 28. 
No. 29. 
No. 30. 
No. 31. 
No. 32. 
No. 33. 
No. 34. 
No. 35. 
No. 36. 
No. 37. 



SK. 
NW. 



NW. 
NW. 
NW. 
W. 
NW. 
NW. 
NW. 



West bank Rio Grande. 
Suniinit of Miilero Mountains. 
Edge of mesa. 
On desert. 
Do. 



On E 



lltll ^ 



On higli, sliarp ridj^e. 
Overlooking Las Palomas Valley. 
East ot Las Palomas Valley. 
Las Palomas Valley. 

Do. 

Do. 

Do. 
North of Las Palomas Lakes. 
Las Palomas Valley, eas 
Laa Palomas Valley, west of Columbus. 
On Mal.P.ais Ridge. 

On slope of liiU south of Tres Heniuinas Mimntains 
On summit of hill south of Tres Hermanas Mouuta: 
In valley southwest of Tres Uermanas Mountains. 



Do. 
On first ridge of Carrizalillo Hills. 
On summit of Carrizalillo Hills. 
In valley south of Carrizjilillo Spring. 
On plain west of Carrizalillo Spring. 

Do. 

Do. 



Views selected 6// the engine 



UNITED STATES AND MEXICAN BOUNDARY. 



\ chief for iUwitraling the joint report of the InternalU 
Slates and Mexico — Continued. 



201 

United 



Remarks. 




No. 69 ' do. 

No. 70 ' do . 

No. 71 do. 

No.72 do . 

No. 73 j Stone.. 

No. 74 1 Iron ... 

No. 75 ' do . 

No. 76 do. 

No. 77 ; Stono.. 

No. 78 ' Iron... 

No. 79 do. 



No.82 Stone 





, 


No. 93 




No. 94 




No.95 


d 






No. 97 


d 


No.98 


Ston 


No. 99 


Iron 


No. 100 


d 


No.lOl 


d 



On ridge of Apache Mountains. 
At nortliwest corner, intersection of parallel 
High ridge of Sierra Rica, meridian section. 
South slope Sierra Rica. 

Do. 

Do. 

Do. 
Near Mosquito Springs. 
On plain south of Mosquito Springs. 



( In Kocky Ridge. 

South end of line on meridian sec 

On plain east of Dog Mountains. 

Do. 
On first ridge of Dog Mountains. 
Summit of Dog Mountains. 
On Dog Mountains. 



In valley. 

On slope of San Luis Mountains. 

On summit of Sail Luis Mountain.^. 

At west foot of San Luis Mountains. 

In valley on old dam. 

In Las Animas Valley. 

Do. 
On high peak of Guadalupe Mountains. 
On Arizona and New Mexican Boundary. 
On summit of High Mountain. 
In Guadalupe Canon. 
On mesa west of Guadalupe Canon. 

Do. 

Do. 
West of San Bernardino River. 
On low ridge. 

On low ridge of Perilla Mountains. 
On high ridge of Perilla Mountains. 
Oil summit of Perilla Mountains. 
In hills near Gallardo Mountain. 
On low ridge west of Gallardo Mountain. 
On plain west of Gallardo Mountain. 



Do. 



On slope east of Mule Mountains. 
On low hill of Mule Mountains. 



On plain west of Mule Mountains. 



On slope west of Mule Mo 

Do. 

Do. 
West of San Pedro River. 
On mesa west of San Pedr 
On Huachiica Mountains. 

Do. 



202 



UNITED STATES AND MEXICAN BOUNDARY. 



I sehcled by the engineers 



chief fur illnstratinr/ the joint report of the Inlernalio 
States and Mexico— Continued. 



il Jloundary Con 



Monument. 


Kind of 


View 
to the— 


Ke,„ark,. 




No. 102 


Iron 


NW. 


On Huacliiica Mountains. 




No. 103 


do.... 


W. 


In west footliills of Huaoliuca Mountains. 








w. 






No lOj 


do 


NE 


On liigli ridge. 
On wide plain. 




No. 106 


Stone 


vr. 




No. 107 


Iron 


sw. 


Do. 




No.108 


Stone 


w. 


Near Zorrillo Creek. 




No.109 


Iron 


w. 


On ridge. 




No. no 


do.... 


]i. 


Do. 




No. Ill 


Stone 


NK. 


West of Santa Cruz River. 




No. 112 


Iron 


W. 


OnLUIivostofLaNoria. 










On east slope of Tatagonia Mountains. 
On liigh ridge of Patagonia Mountains. 




No.lU 


do .... 


W. 




No. 115 


<!"■•■■ 


s\y. 


Do. 






. do 




At west ijase of Patagonia Mountains. 
On mesa west of Patagonia Mountains. 
On i-ast banli of Santa Cruz Kiver. 




No 117 


do 






No.118 


Stone 


w. 




No. 110 


Iron 


E. 


On liill near wagon road. 




No. 120 


do .... 


E. 


On High Mountain. 




No. 121 


do.... 


W. 


On ridge oast of NogaJes. 










On low ridge west of Nogales. 




No. 121! 


do.... 


W. 










In Piviaritos Mountains. 
Do. 




No. 125 


do.... 


NE. 




No. 126 


do.... 








No. 127 


Stone 


NE. 


West end of line on parallel 31° 20'. 




No. 128 


Iron 


NW. 


On ridge of Pajaritos Mountains. 




No. 129 


Stone 


E. 


Do. 




No. 130 


Iron 


NW. 


Do. 




No. 131 


do.... 


NW. 


Do. 




No. 132 


do.... 


NE. 


Do. 




No 133 


do 


E. 
W 


Do. 




No. 134 


.... do.... 


No. 135 


do.... 


E. 


Do. 




No. 136 


StOUL- 


NW. 


On Eresnal Mountain. 




No. 137 


do .... 


NW. 


On liigh, rocky bill. 




No. 138 


Iron 


W. 


On low hill. 




No. 139 


do .... 


E. 


Do, 




No.140 


do.... 


SW. 


Do. 




No.Ul 


Stone 


w. 


On crest of Pozo Verde Mountains. 




No.142 


Iron 


w. 


On mesa west of Pozo Verde Mountains. 




No. 143 






Do. 




No. 144 


do.... 


w. 


Do. 




No. 145 






Do. 




No.146 


Stone 


NE. 


On Moreno Mountains. 




No.147 


Iion 


E. 


On west .slope of Moreno Mountains. 




No.148 


do.... 


W. 


Do. 




No. 149 


do.... 


W. 


Do. 




No. 150 


Stono 


w. 


Near road and high rock. 




No. 151 


Iron 


NW. 


Open level country. 














No. 153 


do.... 


W. 


On Lesna Mountain, very precipitous. 




No. 154 


do .... 


AV. 


On rolling plain. 




No. 155 


do.... 


NW. 


Do. 




No. 156 










No. 157 


do.... 


NW. 


Do. 




No. 158 


do.... 


W. 


Do. 














No. 100 


Stone 


NW. 


On crest of Nariz Mountains. 




No.161 


Iron 


SW. 


In Santa Rosa Valley. 




No. 162 


Stono 


NW. 


On crest of Santa Rosa Mountains. 




No.163 


Iron 


NW. 


On steep spur of Santa Rosa Mountains. 




No. 164 


do.... 


SW. 


In level country west of Santa Rosa Mountains. 





UNITED STATKS AND MEXICAN BOUNDARY. 



203 



Fiiws nelected by the ent/inters hi chief for illiislratlng the joint report of the Intcrnaiional Uniindari/ Commission, United 
States and Mexico — Continued. 



No. 165., 
No. 166., 
No. 167. 
No. 168. 
No. 169 . 
No. 170., 



No. 172- 



No.173 

No.174 , 

No.175 

No.176 

No. 177 

No.178 

No. 179 

No. 180 

No. 181 

No. 182 



No. 184., 
No. 185., 
No. 188. 
No. 187. 
No. 188., 
No. 189. 
No. 190., 
No. 191- 



No. 200 
No. 201. 
No. 202- 



No.20fi 


do.... 


No. 207 


Stone 


No. 208 


Iiou 


No 209 


do 


No. 210 


do... 


No. 211 


....rto...- 


No. 212 


do.... 






No. 214 


do.... 






No. 216 


do.... 






No. 218 


do .... 






No. 220* 


do.... 






No 222 


do 


No. 22) 


do .... 






No. 225 


do.... 


No. 226 


do .... 


No. 227 


do.... 



NW. 
NW. 
S\V. 



. Rosa Moiintaina. 



Ou high hill near Sonoyta. 
On mesa west of Sonoyta. 

Do. 
On hill west of Sonoyta. 
Near Quitobaquita Springs. 
On hilly mesa. 
On plain. 

On high, rocky hill. 
On ridge south of Quitoba.iiiita I 
On mesa. 

On high, lava hill. 
On high hill. 
On Tnio Desert. 

Do. 

Do. 

Do. 
On Tu\,- Mi.uiilaiiis, 
On high, rough inak of Tuhi Mm 
On crest of Tulo Mouutains. 
On west ridge of Tulo Mountain! 
In valley west of Tule Mountain 
On I.echuguilla Mountains. 
Near east ba.se of Tina,ias Alias. 
On crest of Tinajas Mountains. 
On ridge west of Tiua.jas Mounts 
On Yuma Desert. 



On Volcanic Ridgo.Tuma Desert. 
Ou Yuma Desert. 



NW. 


On 


mesa east of Coloratlo I 


W. 


In 


river bottom, east side 


w. 


In 


river bottom, west aide 


w. 


On 


nie.sa near Pilot Knob. 


NW. 


Oi 


me.sa west of Pilot Kn, 


NW. 


On sand hills west of Pilot 


W. 




Do. 


SW. 


On 


Colorado Desert. 


W. 




Do. 


W. 




Do. 


SW. 




Do. 


NW. 




Do. 


w. 




Do. 


NE. 




Do. 


W. 


In 


Sal ton Valley. 



Do. 
East of New River. 
West of New River. 
In New River Valley. 
Lowest point on boundary. 
On spur of Signal Mountain 

Do. 
On Colorado Desert. 



204 



UNITED STATES AND MEXICAN BOUNDARY. 



( lews selected by the engineers in chief for iUiistratiny the joint report <-/ the International Bonndarij Commission, United 
States and Mejcico— Coutiuued. 



No. 228., 
No. 229.. 
No. 230.. 
No. 231.. 



No. 235. 
No. 236. 
No. 237. 



No. 241. 
No. 242. 
No. 243. 
No. 244., 
No. 245.. 
No. 246. 
No. 247.. 
No. 248.. 
No. 249.. 
No. 250.. 
No. 251.. 
Nu. 252. . 
No. 253 . 



No. 257. , 

No. 258.. 
No. 258. . 



Stone . 
Irou . . 



NW. 
NW. 



NW. 
NW. 
NW. 



NW. 

I NW. 



On Colorado Desert. 

On high, rough ridge. 

On high ridge of coast range. 

On summit of coast range. 

In saddle of higit mountain. 

On ridge near Jacumha Spring. 

In Jacuraba Canon. 

On bowlder. 

On hill in Coast Eange. 

Do. 

Do. 

Do. 

Do. 
On high ridge. 

Do. 
On Iiigh hill. 

Near road south of Potrero. 
In valley east of Mount Tecate. 
Ou east crest of Mount Tecate. 
On west crest of Mount Tecate. 
On sharp ridge, west slope of Mount Tecate 
Ou ridge west of Cottouwoud Valley. 
On ridge in Tijuana Valley. 
On south slope of Otay Mountain. 
On Otay Mesa. 



On mesa west of Tijuana Eiver. 
On high mesa near Pacific Ocean 
Old initial monument, reeut. 



Old moniimenta and scenery. 



United States custom-houso, El Paso. 

Parish eliiirch at Juarez. 

Tyjui of uew monument, showing hasr. 

Camp No. 1 of United States section on Kio Grande. 

Ohl Monument No. XVI, East. 

Kebuildiug Monument No. 40. north end of meridian sec 

tiou. 
Mosquito Spring. 

Old monument at south end of meridian section. 
Camj) of United States section at Dog Spring, Now Me.xicj 
Old Monument No. XII ou Sierra de la Nariz. 
Turkey Canon, near Monument No. 66. 
Old monument between New Mexico and Arizona. 
Old monument at San Bernardino Ranch, Ariz. 
Camp of Mexican .section at San Bernardino, Ariz. 
San Bernardino Springs. 
Mexican custom-house, LaMorita. 
Camp of monument party at Bisbee. 
Main camp of United States section at La Noria. 
View ou wagou road east of Nogales. 
Old Monument No. 26, Nogales. 



International street, Nogales. 

Nogales, looking NE. 

Mexican custom-house, Nogales, Sonora. 

Mexican consulate, Nogales, Ariz. 

Old mission, San Jose de Tumacacori. 

Old mission, San Xavier del Bac. 

Erecting Monument No. 1.53 on Cerro de la Lesna. 

Giant cactus, near Tule Mountains. 

Sonoyta River, Sonora. 

Trail to site of Monument No. 184. 

Monument No. 184. 



Camp of Mexican section near Lechuguilla Mountains. 

Las Tinajas Altas. 

Ob.servatory at Monument No. 204. 

Old Monument No. II. 

View of Yuma. 

Barranca Verde Ranch, California. 

Camp of Me.xican section at Hot Springs, Tijuana River. 

Astronomical Observatory, Tijuana. 

Old Monument No. I ou Pacihc. 



BIOLOGICAl, WORK. 

Capt. E. A. Mearns, as.sistant surgeon, U. S. A., was detailed by the War Department to act 
as medical officer for the commissiou, with the uuderstaiidin};' that he would, iu addition to hi.s 
l)rofessional duties, make collections of uatural history along the boundary for the benefit of 



UNITED STATES AND UtEXICAN BOUNDARY. 205 

Dr. Mearns proved bimself to be a most etticieiit uiedifal otticer and an indefatigable and 
successful collector. His services with the couimission extended from January, 1892, to September, 
1894, excepting a few months during which he was assigned to duty at Fort Clark, Tex. This 
interruption did not, however, iirevent him from covering the entire boundary line, as he was able, 
by joining the monument party at a later period, to take up his biological work at the exact point 
where he had left it on being ordered to Fort Clark. His researches along the whole line were 
therefore continuous. 

During this period monthly reports of military and professional duties, in the capacity of 
surgeon of the party, were made by him to the War Department, and monthly reports on the 
biological and other collections, and facts relating thereto, were forwarded through the commission 
to the State Department. 

The scientific work accomplished was of the nature of a biological survey of the Mexican 
boundary region, and agrees essentially with the plan which was submitted to the commission in 
January, 1892, before entering the field. Plants, vertebrate animals (mammals, birds, reptiles, 
batrachiaus, and fishes), molluscs, crustaceans, rocks, minerals, fossils, and a small amount of 
archa-ological and miscellaneous materials were embraced in the collections, which were deposited 
in the United States National Museum. 

About 100 collecting stations were occupied during the course of the survey, which extended 
over a period of nearly three years, and covered an extent of 700 miles of the boundary. Dr. 
Mearns has been stationed at three military posts on the Rio Grande in Texas, and had previously 
served for more than four years in the Territories of Arizona and New Mexico. At each of these 
posts, as well as at each of the collecting stations on the boundary line, an effort was made to 
procure and preserve specimens of each vertebrate animal and flowering plant that could be found, 
in order that the collections might furnish indisputable evidence of the longitudinal dispersal and 
variation of as many species as possible. 

It seemed important that the exceptional facilities alTordcd by this survey for studying the 
degree and manner in which plants and animals vary along a parallel, and if jwssible the laws 
whicli govern such variations, should be utilized as fully as possible. To this end much time 
was devoted by Dr. Mearns to gathering abundant material to show the distribution, and 
variation with locality, of the several species. The longitudinal ranges of the species and sub- 
species (geographic races) were carefully defined, and an approximately accurate knowledge of 
the character and extent of the faunal and floral tracts crossed by the boundary line was 
obtained. 

The collections were made by Dr. Mearns, with the occasional voluntary assistance of other 
members of the party, and of Mr. F. X. Holzner, a collector employed at the doctor's request 
by the United States National Museum, and the American Museum of Natural History, in New 
York. 

A detailed report upon these collections is now being prepared by several specialists to 
•whom the materials of ditterent classes have been distributed. A report upon the Mollusca, 
with illustrations, has been completed by Dr. W. H. Dall, and will soon be published. Miss 
Mary J. Rathbun has prepared an annotated list of the Crustaca' collected, and more or less 
progress has been made upon the other groups. The Mammal report, by Dr. Mearns, is approach- 
ing completion, and a chapter on the birds, also by him, is expected to follow. The mammal 
collection aggregates about 1,000 specimens, and the bird collection nearly 8,000 specimens. The 
collections as a whole compare favorably with those made by any other Government scientific 
expedition, and number about 30,000 specimens, of which number about 10,000 are flowering 
plants, upon which Mr. F. V. Coville is engaged in preparing a special report. 

Several preliminary papers containing descriptions of species new to science and based upon 
this material have been recently published. 



206 UNITED STATES AND MEXICAN HOUNDAKV. 

FINANCIAL STATEMENT. 

a. Tlif field opiralions from Fihriiary, ISn?, to Mail, 1S95. 

Appropriations were niiide by Congress for the expenses of an International Boundary 
Oommission, to survey and remark the existing frontier between tlie United States and Mexico, 
as follows: 

By acts approved— 

Mai-cU3, 1885 $100,(100.00 

September 30, 1890 75, UOO. 00 

August 5, 1892 50,000.00 

$225, 000. 00 

In addition the following amounts ilisbiirstul ou cprtaiu accounts have reverted to appropriation: 
From Mexican Governmeut, being its .share of cost of construction and erection of nionnincnts. $20, 008. tU 

From sales of equipment and 8ub.si8tcnce 0, 736. 08 

26, 804. 72 

Total - 251,804.72 

The field operations, which included the survey, the preparation of preliminary maps, the 
construction and erection of monuments, and photography, were carried on from February, 1892, 
until May, 1895. The principal objects to whicli the exiienditures were applied, and their amounts 
iu each ca.se, are shown in the following list: 

Astronomy : 

(1) Longitude p.irty $1,560.60 

(2) Latitude and azimuth party 9,447.08 

Tangent and monument locating parties 15, 198. 63 

Topographical parties 51, 056. 71 

Photography ,5,684.96 

Construction and erection of monuments 40, 504. 78 

General office and commission expenses 58, 225. 97 

Transportation 69,424.90 

Balance on baud at close of iield work 701. 90 

Total 251,801.72 

In this list the item "Construction and erection of monuments" includes transportation 

pertaining thereto, which sum, .f 16,591.00, is omitted from the item of general transportation, and 

should be added to obtain the gross amount, as shown in the next table. 

The following is a combined table in which the columns show the cost of thedift'erent supplies 

as distributed among the general divisions of the work. These columns are added first in a 



UMTED STATES AND MEXICAN HOtlNDARY. 



207 



line of totals witbout transportation, and tinally with the approximate cost of trausportntiou 
included: 



Gf peral items. 


Astronomy. 


andlocat. 
ing monu- 
ments. 


Topogra- 
phy. 




Cons,n„. 


■ ,;<.,„..:,i 




Total. 


Longi- 
tude by 
telegraph 


Latitude 

and 
azimuth. 


Photog- 
raphy. 


i-r'('''i'i'<'i'n "'.i'l'nh i'." Iranapor- 


Servicea 


$320.42 
958.00 


$6,213.00 
720.00 
39.75 


$11,232.06 

2,852.65 

68.75 


$39,715.11 

8,617.67 

164. 29 


$3,988.08 
400.80 


$8,791.29 
1,563.63 


1 






1,879.25 
00.00 


5,903.52 








Forage 








17,083.21 

1. 024. 00 

230. 42 


17,083.21 


Water 




38.59 
262. 52 

53. 05 

1, 9.34. 35 

109.72 

15,50 


163.24 
176. 03 



79.20 
281. 95 
254.15 

89.70 


307.31 
433.13 

227. 36 
968. 21 
458.05 
105. 58 


2L68 
25.00 

i,ni.i5 


165.82 


25.00 


l'™tage 

Photographic equipment aud 

si'I'Plies ., 

Furniture and office supplies . . . 
Instruments 




1.23 

G. 15 

194.20 

1.10 


1,152.10 






1, 878. 30 




2,239.82 
3. 190 06 






35. 25 


287.75 


86.72 
12.25 


3,481.43 
284.12 




508- 25 
ll,559.;i8 


Monuments and parts 

Cement and lime 





11,559.38 
1,529.18 


110. 68 

1,158.90 

48.89 

24.37 






2.05 
74.93 
1.90 




















123. 82 
26.27 


Postal service 


L. 










Total 

Malni.ii:,.,. rtr.Lnsiiortation... 

E'V ' «:i...n and pack 

Wayuuluruauaiuiriage 

Transportation, rail 

Total transportation 
















1,560.60 9.447.08 
2,980.05 


15, 108. 03 
5.490.60 

0, 222. 57 

19. 25 

1. 562. 03 


51, 056. 71 
19, 510. 30 

9, 110. 22 

00.50 

5,775.69 


.5,084.96 
1,989.05 

50.00 

2.50 

172 .30 


23,913.72 
10,416.94 


58. 225. 97 
13,334.35 


53, 731. 89 


218,809.50 


53,721.89 


15, 604. 28 
2, 97.3. 07 
13,710.72 


77.55 
1,261.55 




2,582.22 
3.591.90 


231. 05 
918. 69 


2.973.07 
13, 716. 72 


434. 56 


1 1 











80, 015. 90 








28,493.08 


85.513.42 


7.899.41 


40,504/78" 


72,710.00 


— .- 







1 


1 


.Dl, 103.0.1 



The final column of this table shows the total cost of each general article of supply, as serv- 
ices, subsistence, etc. To accKrately distribute the cost of transportation so as to show the 
proportionate amount to each article of supply is impracticable, as the records were not kept with 
that view. 

In the case of certain supplies, notably water, the purchase price represents but a minor part 
of the entire cost delivered at the camps, as in some instances water was hauled by rail aud 
wagons over 100 miles, and frequently more than 40 miles by wagons alone. 

A close estimate of the cost of transporting the water used by the United States section of 
the boundary survey can be obtained by computing the cost of maintaining the several water tank 
wagons used exclusively for supplying water. 

Three of these wagons were used from the beginning to near the close of operations, and a 
fourth during a shorter period. The cost of maintaining each of these wagons averaged $105 per 
month; the number of months during which all the water wagons were in use was equal to !»(> 
for one wagon, making cost of maintaining $10,080, to which should be added the original cost of 
the equipment less the amount received from its sale, giving $12,500 as the cost of transportation 
of water. If there be added the payments for water purchased, and a due proportion of the cost 
of supervision of transportation, the aggregate cost of water used would he shown to be about 
$10,000. The supply used by the escort was provided by its own tank wagon, aud does not appear 
in the above computation. 

In the same way it might be shown that the cost of forage, subsistence, etc., delivered at the 
camps was largely in excess of the first cost of those articles. 

The column next to the final one shows the several items which make uj) the aggregate of the 
transportation. Its approximate distribution is shown under the different divisions of the work. 

Although this entire sum of $80,015.90 was disbursed for transportation, it should be 
diminished by the net receipts on account of sales of equipment in order to show the exact cost to 
the appropriation. Likewise, from the aggregate sum of all the disbursements should be taken 



208 UNITED STATES AND MEXICAN BOUNDARY. 

the aiaount received from the Mexican Govenimeut as a reimbursement, and the full amount 
received from sales, etc. This would leave $224,298.91 as the true amount applied from the 
original appropriations to the Held work; if to this the balance of $701.09 be added, the result 
will equal the total appropriation, $225,000. 

/). The office work, preparini/ reports and maps, from October, 1S95, to Norember, tS9G. 

Balance remaining from previous appropriations $701. 09 

Amount disallowed ou previous accounts and refunded 1.57 

Amount appropriated by act of Congress approved February 26, 1896 20, 000. 00 

Total 20,702.66 

Expended iu compliance witli the act, as follows: 

Salaries, draftsmen, preparin g maps $2, 38.'>. 62 

Salaries, clerical, etc 1,735.95 

Engraving 20 copperplates, one-half cost 4, 135.00 

Electrotyping same, one-half cost 1, 000. 00 

Prepariug half-tone plate.s of 300 photographs and jirintiug proofs 239. 70 

Photolithographing, profiles 200.00 

Photolithographiug, miscellaneous sheets 16.00 

Rent of office 1,052.50 

Furniture and office supplies 422. 75 

Incidentals 255.04 

13, 543. 16 

Balance on hand at completion of final report 7, 159. .50 

20, 702. 66 

CHAPTER IX. 

DESCRIPTION OF MAPS, PROFILES, AND PLATES. 

A map of the entire boundary line from the Rio (irande to the Pacific in 18 sheets, ou a scale 
of 1-^00,000, accompanies this report. The sheets are each 1 meter long and show a belt of 
topography of 5 miles in width, 2.i miles on the north side of the line being drawn from the 
surveys of the United States section of the commission, and a width of 2i miles on the south 
side of the line drawn from the surveys made by the Mexican section of the commission. Each 
monument is located in its true position on these sheets. 

One additional sheet, making 19 sheets in all, shows the Rio Colorado where it forms part of 
the boundary. As this river was surveyed in March, 1893, by the United States section, and in 
February and March, 1894, by the Mexican section, the channel of the river is not the same, as 
determined by the two sections, and the two surveys are shown ou one sheet by printitig the 
maps of the two surveys in different colors. 

Five sheets of profile of the boundary on a scale of 1-^60,000 horizontal and 1-^0,000 vertical 
are submitted. This profile is drawn from the levelings of the United States section, and gives 
the height of the masonry base of each monument above mean sea level of San Diego Bay. 

An index map of the boundary line in 2 sheets, ou a scale of 1-^600,000, is also submitted. 
This map shows the limits of each of the 19 sheets of the boundary, and also gives the location 
and the height of all the principal peaks in the vicinity of the boundary line as determined by the 
United States section of the commission, and also the roads, trails, springs, wells, and water holes 
as determined by the surveys of the United States section. 

The railroads, roads, and settlements distant from the boundary line were compiled from the 
best maps available, including county maps of New Mexico, Arizona, and California, the United 
States Land-OfiUce maps, those of the War Department, etc. The coast line of the Pacific north 
of the boundary was taken from the Coast and Geodetic Survey charts, and the coast of Lower 
California and the shore line of the Gulf of California from Hydrographic Office maps of the 
United States Navy Department. 

The maps of the boundary submitted, including the index sheets, are prints from 22 copper- 
plates, which are preserved for future use. These plates will admit of but a limited number of 



UNITED STATES AfiD MEXICAN BOUNDARY. 209 

clear impressions (about 4,000 or 5,000); therefore, if a larger edition is required, the jirinting 
should be done either from electrotype copies of these plates or by photolithography. 

The drawings of the proliles were not engraved; the 20 copies submitted were made by 
photholithography at the establishment of the Norris Peters Company, where other editions can 
bo obtained from the photographs retained there. 

CILVPTER X.— APPE^TDIX. 

REPORT OF LEONARD SEWAL SMITH, ASSISTANT PROFESSOR, UNIVERSITY OF WISCONSIN, 
ON THE CAUSES OF SYSTEMATIC ERROR IN STADIA WORK. 

(Mr. SiuHli served as transitnian on this survey.] 

AN EXPERIMENTAL STUDY OF FIELD METHODS WHICH WILL INSURE TO STADIA MEASURE- 
MENTS GREATLY INCREASED ACOURACV. 

I. Introduction. 

The rapidly increasing interest in the subject of stadia measurements, due to its wideiiing 
field of application, is bringing about a revolution in some of the established methods of field 
l)ractice in this country. The superiority of the stadia, both in accuracy and in cost, over the 
chain in broken country is already firmly established, and late experience has shown equal merit 
in the measurements of long lines in flat regions. 

The method is especially adapted for taking topography and hydrography,* with or without 
the control of a triangulatioii, for meandering roads and rivers, and for making preliminary 
railroad surveys.t The writer's conclusions, given in this report, show that the method has a 
much wider field of usefulness. 

The collection of data for this report was begun during the field work of the International 
Boundary Survey, United States and Mexico, 1892-93, merely as a study of a certain atmosijheric 
phenomenon, commonly called by engineers "boiling.'' In the summer of 1894 this work was 
continued in Wisconsin, but was also made to include an experimental study of the effect of this 
"boiling" of the air upon the accuracy of stadia measurements. During this latter work the 
all-important effect on such work, of what the writer has called difterential refraction, was forced 
upon his attention and studied in detail. This part of the study, it is believed, furnishes the 
most valuable results of the whole investigation, for it is here shown that in this unsuspected 
phenomenon lies the reason that the accuracy of stadia measurements has in the past been limited 
to about 1 700. 

It is well known among engineers that measurements made by the link chain, as commonly 
used, are subject to large systematic errors, principally due to wearing at its several hundred 
bearing surfaces, failure to hold it horizontally, expansion, and stretch. 

On the other hand, since stadia measurements are subject theoretically only to compensatory 
errors, to insure superior results it should only be necessary to secure small probable errors of 
single sights. Practical results, however, have been uniformly disappointing, for, while the 
accidental errors of observation have always been within proper limits, care has not been fal-en to 
remove the causes of systematic errors, chief among which is what the writer has called differential 
refraction. That such systematic errors can be prevented or greatly modified by improved field 
methods the experimental work discussed by this paper seems clearly to have proved. This 
report gives the writer's results to date, but it is believed that the subject is worthy of continued 
study. 

It is hoped that the method here used of investigating facts by extensive experiments rather 
than by purely theoretical considerations may appeal to the confidence of the practical field 
engineer. The writer's thanks for criticisms and suggestions upon the plan of the work are due 

* For a description of such a survey see paper by J. L. Van Ornum iu Journal of the Association of Engineering 
Societies, Vol. XIV, p. 219. 

tSee description of such a survey iu Journal uf the Association of Engiueering Societies, Vol. XII, p. 411. 



210 UNITED STATES AND MEXICAN BOUNDARY. 

to Prof. J. B. Johnson and ^Ir. J. L. Van Ormim C. E., of Wasliingtoii University; Prof. Wm. 
Raymond, of Rensselaer Polyteehuic Institute; Prof. Ira O. Baker, of the University of Illinois; Mr, 
B. H. Colby, of St. Louis, and Mr. A. 0. Schrader, C. E., of the Ohicago sanitary district; but 
especially are bis thanks due to Prof. George C. Comstock, of the University of Wisconsin, who, 
by reason of his long continued and painstaking study of atmospheric refraction, has been able to 
make clear the significance of much experimental woik. 

U. Study of Atmospheric Unsteadiness. 

This report will deal with, first, the behavior of the air under various atmospheric conditions; 
second, the effect of such behavior in pi-odncing accumulative errors of stadia measurements, 
and, third, a discussion of the proper remedy. Experiments to determine the first point were 
made in the years 1892-93 while the writer was engaged as transit man and topographer on the 
International Boundary Survey between the United States and Mexico. 

The wlioh^ line from El Paso to the Pacific Ocean, a distance of about 700 miles, was measured 
by the stadia method, and all accurate contour tojiography in a 2i mile be t along nearly the whole 
distance was taken by the transit and stadia. The first 100 miles was also measured by chain,* 
and a former triangulation, and longitude determinations by the United States Coast and Geodetic 
Survey gave additional checks. 

All connected with this work were early impressed by two facts, namely, the surprisingly high 
degree of accuracy and speed obtainable by the stadia, and the completeness with which this 
accuracy and speed were governed by the peculiar unsteadiness of the air, which engineers call 
"boiling" or "vibration." 

With a view to discovering, if possible, the conditions governing this "boiling," a series of 
observations were recorded as fully as at first seemed necessary. f Only odd hours were at first 
given to the purpose; but later, while camped at the east base of the Tule Mountains, and near 
the middle of the Yuma Desert, a more extended and valuable series of observations was taken. 
The first observations were made on the New Mexico line, June 19, 1892, and the last on the 
Arizona line, July 25, 189.3. This work has also been continued in Wisconsin. 

(ft) Method of work. — Tlie first observations are lacking in data which afterwards were found 
to be very essential, namely, the temperature of the air when observations were taken, and the 
number of vibrations per minute of the recorded amplitude. 

In these experiments inch Brandis transits, weighing (including tripod) 25 pounds each, 
were used. The average focal length of these was 19 cm. and the constant c was 10 cm. The 
telescope magnified about 20 diameters and gave remarkably good definition. The rod was 
graduated in the metric system in the manner shown by fig. 1 (pi. 1). Its total length was 
4.5 m., width 0.1 m., and thickness 2J cm. The characters were white and black, with red at the 
meter and half meter points in place of the black. 

The target used was made by painting on the back of the stadia rod and at a distance of 2 m. 
from its foot black and white stripes of the width indicated in fig. 2 (pi. 1); but later, when paint 
became scarce, strips of black and white cloth were used instead. 

The method of work was as follows: A rodman was sent in a given direction, with instructions 
to show the graduated face of his rod at every 100 or 150 paces, and to follow this, on signal, by 
the back containing the target. The first movement allowed the stadia to be read, and the second 
allowed the amplitude of the heat weaves at that distance to be studied. This was continued for a 
distance never greater than 1,000 meters (five-eighths of a mile) and usually less than 800 meters 
(one-half mile). The limitation of distance was made for two reasons: first, beyond 800 m. the 
target became so irregular and indistinct that, except under very favorable circumstances, results 
were comparatively worthless, and, secoud, as in taking topography but few sights exceed 800 m., 
tests on longer distances were without interest. 

In observing the middle horizontal cross wire was, by means of the gradienter screw, always 
put so as to bisect one of the stripes of the target, selecting for the experiment that stripe which 
was found would most nearly equal the amplitude of the vibration. 



* In this first 100 miles the writer's statlia measuremeut detected six errors of 20 meters each (i. e., a whole 
o). Both chain men were intelligent men and had had previous experience in similar Government work. 
t This work was begun at the suggestion of Mr. J. L. Van Ornum, assistant engineer. 



UNITKD STATKS AND MEXICAN HOVNDARY. 



211 



Later it seemed desirable to record the number ofsiieh vibrations per minute, and for ease iu 
observing tiiem the apparent swiug of tlie wire from one edge of the stripe to the other was called 
one vibration ; then back to its original position, tico vibrations. The wire having a considerable 
thickness, doubtless introduced an error because of the ditficulty in judging the coincidence of the 
middle point with the upper and lower limit of the target. This error, affecting all sights in nearly 
the same ratio, would not necessarily change their relative amounts, which was the important 
thing sought. Moreover, each experiment was usually repeated several times, and the mean 
result recorded. This was necessary, since, during the hours of greatest disturbance, the number 
of vibrations during consecutive minutes would frequently differ greatly. The number of vibra- 
tions would even group themselves sometimes so that 20 seconds would contain as many vibrations 
as the following GO. These i)eriods of greatest activity appeared to come in the intervals between 
the slight breezes, when the air was still. During such intervals the effects of the heat waves 
seemed to accumulate until at times the vibrations became too numerous to count, only to be 
blown aside by the next breeze, and the process repeated. 

(b) Lateral vibration. — If the breeze became a steady and not too violent 
one, the air had the appearance, when viewed through the transit, of a 
mighty river rushing madly along in the direction of the wind. The effect 
of this movement upon the appearance of the rod was nmrked. The diffeient 
areas of color (diamond shaped) changed form rapidly, the distortion con- 
sisting in irregular tongues of color leai)ing laterally from the general line 
of the rod and dovetailing into the adjoining color, so that the rod ajipeared 
to be bounded by a constantly changing, irregular line (fig. 3). The lee- 
ward side of the lod was always more affected by this disfigurement than 
the windward side. 

Except in very windy weather this lateral vibration seemed to have 
a progressive wave movenieut along the rod, and always from the bottom 
toward the top, giviug to the rod a peculiar snaky appearance. The lateral 
vibration was always considerably greater at the bottom than at the top of 
the rod, and frequently e<pialed in amplitude the vertical vibration observed 
at the same distance.* 

While this lateral vibration is of vital importance to correct pointings 
in the measurements of horizontal angles, it is believed that it only indi 
rectly affects the accuracy of a stadia measurement by decreasing tlie 
distinctness of the image.t It was accordingly less carefully studied than 
other phenomena. 

(c) Vertical vibration. — lu addition to the lateral vibration in nearly 
every observation, two distinct classes of vertical vibrations were observed, diflering both in 
amplitude and period. One class consisted in a very (piick and comparatively uniform amplitude, 



Target. 




Fig-. 3. 
Effect of Vibration 
on Target. 



Cross ^^^^H 



"SE^aHr 



Fig'. 4. Typical Vertical Vibrations. 



and the second consi.sted in vibrations of much greater amplitude, but very much smaller in 
number per second. The latter will be called the xjrimary vibrations; the former, the secondary 
vibrations. 

' Iu making these experiments care was taken to guard against any movements of the transit, its parts all 
being firmly clamped. The tnpod, too, was always firmly planted in the ground, and, when required to steady it, 
rocks were placed around the legs. It was early discovered that a stiff, gusty wind gave very irregular and 
unreliable results, in spite of all precaution, so that experiments were finally attempted only in favorable weather. 

tThis phase of the subject, with especial reference to pointings on heliotropes, has been very ably discussed by 
Mr. ,T. F. Hayford, assistant astronomer on the International Boundary Survey. .See Appendix IV, Chapter IV, 
Report of the United States Section. 



212 UNITED STATES AND MEXICAN BOUNDARY. 

The manner in which these two systems would occur can be best shown by a diagram (fig. 4). 
Suppose the experiment was with the blacli stripe, A, B, C, I), one decimeter square. The middle 
cross wire was put so as to bisect the figure in the beginning, and was corrected anew whenever 
the amount of vibration above the middle line differed from that below the same line. If the cross 
wire could record its apparent motion in the same way that a vibrating tuning fork does when 
dragged along a smoked glass, it would describe a path like that in fig. 4. Thus, if B — D limits the 
extreme highest and lowest positions of the cross wire, i, e., the amplitude of the primary vibration, 
those positions will be reached only through the zigzag path constituting the secondary system of 
vibrations. In other words, the irregularities of the path may be considered due to the super- 
imposed secondary vibration. 

{d) Vibration causes only accidental errors. — In a general way, the primary vibrations seem to 
be less regular than the secondary, and, in the writer's judgment, affect to a greater extent the 
accuracy of a stadia measurement. This is true for the following reason: When a stadia 
measurement is made, the lower cross wire of the telescope is put on an even unit, and then the 
upper wire is instantly read. Now, if the only disturbance of the air was that due to the 
secondary vibration, the average position of either wire would remain nearly constant in position 
and could be readily found, so the intercept should be subject to but slight error. 

With both movements present, it is much more difficult to find the average jtosition of the 
lower wire; and even when found, while the eye glances up to read tlie upper wire the irregular 
primary vibration may make the upper wire read seriously in error; nor can time be spared to 
study the average position of the upper wire, as was done with the lower one, because the telescope 
is constantly changing its position even when clamped, and though this movement occurs within 
small limits, it is large enough to make the previously determined position of the lotcer wire 
wrong, and so decrease the accuracy of the sight. When the vibration is excessive, this movement 
is sufficiently large to make any single reading seriously in error, but such errors are as likely to 
be positive as negatioe, and therefore follow the law of compensating errors. The cause of 
systematic en-or is evidently not here. 

(e) Typical curves. — The manner in which the amount of this vibration is inffuenced by length 
of sight, hour of day, brightness of sun, and temperature can best be shown by typical curves 
representing actual observations. In fig. 5 the x abscissas of the curves are the lengths of sights 
in meters, and the y ordinates are the recorded amplitudes of the vertical swing of the cross wire. 
The time of greatest disturbance at the date and locality (Sonoyta, Mexico, June 14), represented 
by the curve, was 10.30 a. m.; and in general, all experiments in any season, show that the maxi- 
mum unsteadiness of the air comes not during the hour when the air is at its maximum temper- 
ature, but during the hour when the difference in the temi)erature of the air and the earth is 
a maxinnim.* Thus, in figs. 5, 6, and 7 the maximum unsteadiness comes with a temperature of 
87.0° F., and the minimum unsteadiness with a maximum temperature of 98.0° F., at 3 p. m. At 
4 p. m. the falling temperature is followed by a decreased unsteadiness, and the fall is gradually 
accelerated until, at G o'clock, not the slightest glimmering is observable even at long distances. 

In the summer a second maximum period of unsteadiness is observed just as the sun rises 
above the horizon, but it continues for only a half hour, after which interval the equilibrium of the 
air seems to be restored. t 

' The iiiisteadiiiess of the air over the ice of Lake Mendota, Wisconsin, the present spring has been observed by 
the writer to be as great as it is in the middle of the Yuma Desert, with a temperature of 118" F. in the shade. 

t The writer recalls one instance when his party began to determine the interval of transit before sunrise, but 
upon the appearance of the sun the increased unsteadiness compelled the postponement of the work. After a period 
of 30 or 40 minutes the air was quiet again and the work was completed without difficulty. 



UNITED STATES AND MEXICAN BOUNDARY. 



213 



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Bern. 


Fig. 7. 




/. 












1893. 






Icm.. 


^-' 


,^ 


y 






7 


7./S 










*- 




^-^ 


^ 








X 








/ 


'lO 


36 


40 


s 


so 


7C 


a-c 


OMetres. 









Figs. 5, 6, ami 7— Typical ilisturbancK curves showiDg effect of hour of day and length of sight ( 
degree of unsteadiness. X= distance of sight. r= amplitude of vibration. 



214 



UNITED STATES AND MEXICAN BOUNDARY. 



The effect of both leugth of sight and hour of day is more clearly seen by reference to Fig. 8. 
Here the values of *■ are the hours of the day and those of y the amplitudes of the vibratiou of 
the line of sight. This curve may be said to be typical of sunny days during all except the 
cold winter months. 




Y 






Fig.9. 






1 


























Ale. 


mrr.Ar 


17.., 


4 cm. 






Tei 


^P.8s'n 


Sun bn 


iht. 


V^e/a, 








3 cm. 








/ 














2 cm. 






/ 




<3y/ Sh^ 


ht c/ouc 


s. 


■0/33 






tcm. 




y 


/y 




Ji> 


Sun ob 


-.cured. 


%^3 






-^ 




^^^^' 


^ 








X 








n 


>0 2t 


V .ic 


9i 


s^ 


W Metre 


s. 











T— amplitude of vibration. 

During a cloudy day, even with high temperature, but little unsteadiness is observetl, and 
the curve representiug the unsteadiness through the day would be a very Hat one. 

The effect of different amounts of clouds on this unsteadiness is clearly shown by fig. 9, which 
records a measurement of it at the same hour of different days, under almost exactly the same 
conditions (soil, vegetation, temperature, etc.), but differing in the amount of clouds present when 



UNITED STATES AND MEXICAN liOUNDAKY. 



215 



the test was made. It will be seen that with the suu entirely obscured the curve is a straight 
line, with a bright sun an abrupt curve, and with the sun partly obscured the curve takes an 
intermediate position. 

It is thought that the product of the number of vibrations per minute and their amplitude 
is a better measure of the amount of unsteadiness than either factor alone. Using this product 
for the values of y, and the hours of the day for values of x, the curves shown in figs. 10 and 11 
are obtained, which very clearly indicate the hour of maximum unsteadiness, as well as the rate 
of change in the amount of unsteadiness as the length of sight is increased.* 




' aod distance. Ttile Mountains, Arizona. 
btT of vibrations by their amiilitude. 



In tig. 12 the product "f the number and the amplitude of the vibrations is used for the values 
of y and the length of sight for the values of .r, giving a separate curve for each hour when tests 
were made. As in figs. 5, 0, and 7 a marked difference is seen in the curves representing the 
condition of the air three hours before noon from those representing its conditions three hours 
after noon, the latter indicating much less unsteadiness; and, in general, afternoon curves are 
flatter than forenoon curves, as is well shown in tigs. 6 and 7. This pi-obably means that, though 
the temperature of the air steadily increases up to 3 p. m., the temperature of the ground which, 
in the caiiy morning had lagged behind that of the air, now increases more rapidly than the air, 
so that the actual difference in temperature of earth and air, which is the controlling cause of the 
unsteadiness, reaches a maximum by 11 o'clock, and then decreases as the day advances. 

*The actual shajie of tlie curves varies witli a multitude of minor conditions besides those discus.sed, such as 
season, locality, vegetation, amount of moisture in air, soil, etc., but the cnrvcs given are selected from a large 
unmber as showing the average eti'ect on unsteadiness of the conditions studied. 



216 



UNITED STATES AND MEXICAN BOUNDARY. 



Another interesting example of the eft'ect of clouds on the unsteadiness is illustrated in tig. 12. 
The field notes show that at about 10.45 a. m., and immediately after the test platted at M, the 
suu became obscured by a thick cloud. As a result the " boiling" at once decreased iu amount, as 




Sonnj ta, Mexico, .June 14, 1893. 

is shown by the abrupt descent of the curve from M M'. It was fouud that both the number and 
amplitude of the vibrations were increased when the suu shone on the rod, but the additional 
clearness of the image, because of better illumination, much more than comi^ensated for the loss 



UNITED STATICS AND MEXICAN BOUNDARY. 



217 



of same due to the increased misteiuliiiess of the air. Because of this, when making a test read- 
ing, the rotlman was always sent in a direction which would allow the suu to shine on the rod, 
unless this was rendered impossible by the topogpayhy. 



/ 








IZ . 


\ 95° F. 




















\ 
























e.3 


81° F 




















/ 




















1 / 


















CLOL 


'OY. ^ 1 


'/ 




LAW. 


X = Lena 

Y^Prod 

of VI 

their 


th of sig 
■xct of n 
'yrafions 
a.mplitu 


umber- 

and 

de. 








sm 




\ 


















BR /GMT. 

1 




V 


9/V 




















777' 






'A.M. 










10.30-1 






■1, 


C 




100° F. __ 
















1 


1 ^/ 


3 P.I 




'-^' 4 p. 


W. 










• 




III. 


// 


^ 
















/ 


//J/ 


/ 
















^ 


^ 


y/ 










X 








/! 


2i 


3i 


4C 


Si 


6i 


Metrei 











Fig. 12.— Disturbance curves abowiufj ellect of hour and distance, temperature and clouds, Sonoyta, Mex., June 14, 1893. 

S. Doc. 247 18 



218 



UISITED STATES AND MEXICAN BOUNDARY. 



III. Study uf Diffehential Kkfkaction. 

(«)• Relation between unsteadiness and refraction. — It Las been shown that the errors intro- 
duced into stadia work by the "boiling" or vibration of the air are compensatory in their natnre; 
but, while engnoed in .studying such behavior of the air on a base line, in Wisconsin, during 
August, 1894, it was noticed that rod readings, made when such boiling was very marked, dittered 



Y 
























\ 






















\ 






















\ 










Law. 


Y= PrSa 
of V 
their 


t of far 
ucf of n 
'bration 
amplit 


urrjber 
y and 
cde. 








\ 
























\ 


400 ^ 


'ET/!ES. 




















^^ 


~~^ 


^__ 
































\ 




\ 


















\ 




\ 


^ 


300 


























^ 


~ ' 


• 










V 






















\ 




200 






















WO 














0. 


SM. 
















X 












\ 

\ 


//. 



Fig. 13.— Disturbance curves, showing effect of height of line of sight. Temperature 95=-97' at 10 o'cloclf, 
Lesna Mountains, Ariz., July 25,1893. 

widely from those made under steady conditions of air. As this diflerence was found to be a 
systematic one, a careful study was made to determine its cause. It was soon apparent tliut this 
cause was what the writer, for want of a better name, has called "differential refraction.'" As 
used in this paper, the term "differential refraction" e.Kpiesses the difference in the amounts by 
which the two lines of sight, upper and lower, are refracted by the air. 



UNITED STATES AND MEXICAN BOUNDAKY. 



219 



It is known that in the nioriiiug, before the earth and air receive heat from the snu, the density 
of the air is greatest at the surface of the earth, and decreases upward. Eays of light in the 
stratum nearest the ground are refracted downward, i. e., positively. But later on, in a sunny 

























\ 


\ 










LdLW. 


X = Heiah 

Y= Prodi 
Of vil 
their 


' of targ 
ct of nu 
rations 
^TnpHtuc 


■t. 

ruber 

ind 

e. 




\ 


<■ 


\ 


















\ 


\ 


^^ 


""—- 




400 




Temp 


98.'F 






Metres. 






\ 


\ 






















\ 


"-- 


--_ 
























300 












\ 






















N 


V, 
























^ 


-^ 





___200_ 














































































^^^--. 


^^ 








100 












.0 


5 1 

L 


M. 






, 




4 


M. 

1 


X 





Flii. 14. ^Distil 



showing etfect of height of 1 



j'clock July 25, 1893. 



day, the temperature of the stratum of air in contact with the earth becomes highly heated by the 
radiation of lieat from the earth. This increased temperature causes a rarefaction, whicli, within 
a short distance from the ground, makes tlie deusity of the air increase with the distance from the 



220 



UNITED STATES AND MEXICAN BOUNDARY. 



surfuce. Rays of light traversing this portiou of the air are beut upward, i. e., negatively, in 
accordance with the general law that refraction bends a ray of light toward the denser part of 
the medium through which the ray passes. 

A great many experiments were attempted to deterniiue the deptli of this abnormal stratum, 
some of which gave interesting results. It seems certain that, while the total depth cf this 
stratum varies at different hours and seasons, still, the depth of the portiou of it in which the 
change in density is most rapid is seldom more than 3 or 4 feet. If the lower line of sight of a 
reading traverses this lower stratum, it suffers a much greater refraction than the upper line of 
sight. If both happen to be refracted in the same direction, the error in the rod reading is the 
difference of the refractions. If the two lines of sight be refracted in opposite directions, the error 
in the rod reading is evidently the sum of the refractions. 

In the summer of 1893, while camped near the Cerro de la Lesna, a careful series of experi 
meuts was made to determine the relative amounts of unsteadiness in the strata of air from 
^ meter to i meters above the ground. These experiments, repeated in Wisconsin the past 
summer, gave similar results, which are shown in a graphical form in the curves, figs. 13 and 14. 
The X abscissa in these curves is the distance of the target above the ground, the y ordinate 
is the product of the amplitude of vibrations and their number per minute. 

In every experiment it was found that the 
amounts of unsteadiness in strata between 4 m. and 
1 m. above the ground increased only slowly as the 
strata tested neared the ground, while between 1 m. 
and h m. this unsteadiness increased eery rapidly as 
the strata neared the ground. For example, at 10 
a. m., July 25, 181)3, with the temperature 95'= F., and 
with the target 20(1 uu-tcrs distant, the amounts of 
unsteadiness at 4, 1, and i meters above the ground 
were to each other as 5:C:9; that is, the rate of 
change of disturbance between h and 1 meter was 18 
times that between 1 meter and 4 meters (fig. 13). 
The average ratio, with tests at 100, 200, 300, and 
400 meters distant, at the same hour was 7:11:15^; 
that is, the average rate of change in amounts of 
disturbance between strata i and 1 meter above the ground was 5 times the rate in strata between 
1 meter and 4 meters above the ground.* 

(h) A probable explanation. — A probable explanation t of this remarkable fact may be found in 
the peculiar funnel shape of the ascending currents of air caused by the radiation of heat from the 
various materials of the ground along the line of sight. Such currents (fig. 15) have l)een observed 
to rapidly contract as they rise, owing to the pressure of cooler air, but, becoming cooled by 
contact with the surrounding cooler air, they finally spread out laterally and, mixing with cooi 
air, return again to the surface of the ground, thus completing a cycle. J It is probable that the 
lateral spreading of the column of air does not take place within the limits affecting stadia work, 
viz, 15 feet. 

Such a rarified current of air acts like a great lens, but one whose slia])e constantly changes 
with every little breeze or is completely destroyed by a strong wind. When the rays of light 
traverse such a lens nearly at right angles to its axis, those rays which are near the ground suffer 
the greatest refraction. This is illustrated by the following experiment: A 4iuch oil burner was 
put just below the line of sight between the transit and a taiget, and the refraction was measured ; 
then the distance of the line of sight above the burner was increased, upon which the refraction 
diminished. 

An experiment was performed to determine the effect of making the opposite sides of the ascend 
ing column of air as nearly parallel as possible by entirely inclosing it with shutters, hung from 

* Unless otherwise stateil, the height of target is 2 m. above the ground. 

tit should be noted that the final conclusions of this v>aper do not depend upon this hypothesis. 
tNo such definite line as shown in the figure separates tlie ascending current from the surrounding cooler air, 
hut the elfect on refraction is the same as though such were the case. 




I'NITED STATES AND MEXICAN BOUNDARY. 



221 



the ceiling, excepting at a narrow aperture left to allow the transmission of the line of sight to 
the target; but even when tlie line of sight -was as nearly as possible perpendicular to the parallel 
surfaces, refraction was still evident, though in less degree. These experiments were performed 
in the basement of Science Hall, University of Wisconsin, where the strata of air were known to 
1)1' horizontal. When performed in the open air similar results were obtained, but the refraction 
was less steady in amount aiul direction, owiTig to the chaTiging form of the refracting medium. 
The distance between the target a;id the transit remaining constant, it was found that the amount 
of refraction was increased as the burner ap])roached the transit. 

A perfectly lioinogeueous soil, or soil covering, is seldom found in nature. Each exposed belt 
of sand, clay, loam, gravel, or rock, eacli mantle of vegetation, will absorb from the sun and give 
olf heat to the superimposed air according to its own rate of absorption and radiation. This gives 
rise to ascending air currents of ditferent densities, and corresponding indices of refraction. The 
almost iTifinite variety of ways in which a ray of light traverses the large number of such currents, 
when intluenced by every gust of wind, great and small, gives rise to the peculiar fluctuations of 
the line of sight, which have been called primary and secondary vibrations; the former due to air 
currents near the transit, and the latter due to currents near the rod. It was found impractical 
to test the strata of air lower tlian one-half meter above the ground, because of the unevenness of 
tiie surface, but during several years of field work, both in the Southern and jSTorthei-n States, it 
lias been a matter of almost daily experience that a line of sight, passing tangent to the ground, 
e\en at but one point, always sutfered an extraordinary disturbance. A longer path in sucli a 
stiatum would naturally be expected to augment the disturbance. On the other hand, if the line 
of sight passes over a valley so as to lemove the line of sight from the ground, little or no disturb- 
ance is ever noiiccd, even on extremely long sights. 

(f) Expert men tdl eriilenee of diferent'ml refraction. — Additional evidence of the increased 
refraction in the stratum next to the ground is furnished by some careful experiments* made in 
Wisconsin during the past summer, a record of which is shown in Table 1. 



■ll^s 



nigh lin. 


of sight. 


Low line 


ofsiglit. 


True dis- 
' tance. 


stadia dis- 


Error of 
st...,,.a. 


Stadia dis- 


Error of 
8tadi.i. 


Meters. 


Meters. 


Meters. 


Meters. 


Meters. 


487.48 


—0.27 


484.46 


— 3.29 


487. 75 


458.57 


+1.31 


455.57 


-1.69 


407. 26 


427.49 


+0.71 


424.70 




426. 78 


3%. 80 


-1-0.51 


395. 01 


-1.28 


390.29 


36G.42 


+0 61 


365.02 


— 0.79 


365. 81 


335.04 


-0.29 


332. 69 


— 2.64 


335. 33 


304. 66 


-0.18 


302.97 


— 1.87 


304.84 


2770.46 


+2.40 


2760. 42 


—13.64 


2774. 06 


+ n'^ 


= error. 


-ii= = 


= error. 



After reading the stadia every 100 feet between station 304.84 m. (1,000 feet) and station 
4S7.75 m. (1,000 feet) with the usual height of instrument (1.4 m.), the same distances were read 
with the transit on the (/round ( i. e., H. I. = 0.25 m.). It will be seen that the latter readings 
show a very much larger error, all in the same direction (systematic), whose sum is the total 
distance so measured as 1 : 160, while the uncompensated errors with the instrument at its ordinary 
height were not of the same sign (i. e., not systematic), and their algebraic sum i.s to the distance 
as 1 : 115.5. It should be noticed that the readings with the least height of instrument gave such 
uiiilornily large systematic errors as to entirely cover up the accidental ones, while with the normal 
hciglit of instrument, the upper and clearer portions of the rod being used, the presence of about 

*In jiistice, to these experiments It should be stated th.at at the time tliey were iii.adc the writer li.ad suth 
ideas ou this subject that the results of the experimeuts were .a complete surprise to liim. 



222 



UNITED STATES AND MEXICAN BOUNDARY. 



an equal number of phis and minus errors sbows tliat the cause for systematic errors was no 
longer present. 

The reason for this marked change will be understood when it is remembered that the lower 
line of sight in the first case traveled its whole length in a rapidly varying stratum of maximum 
disturbance, while the upper line of sight traveled the larger part of its length in strata of 
comparatively little and uniform disturbance. This is well illustrated in figs. 16 and 17. In 
fig. 1() both lines of sight would be refracted in the same direction — B to B', A to A'; that is, 
the concavity of their paths would be turned toward the denser air. This would make both 
readings too large, and if both lines were refracted equal amounts no error in the intercept 




would result. However, such is not the case. Under such conditions the distance BB' always 
exceeds AA', and the resulting error is AA'— BB'. This explains the uniform minus error with 
low height of instrument. The normal height of the instrument taken (represented by fig. 17) 
brings the lower line of sight entirely above the stratum of greatest disturbance, while that of 
the upper line of sight traverses strata which it has been shown differ but slightly from that 
traversed by the lower line of sight. Both lines are, as "u the previous cases, refracted in the 
same direction, but in very nearly equal amounts; hence the intercept suffers but a slight error. 

The fact that the sum of the two half interval readings on the upper and clearer jioition of 
the rod almost invariably exceeded the full interval reading had been repeatedly noticed in the 




field work of the International Boundary Survey, but not until the results of this experimental 
work were studied was the cause for the disagreement made clear. 

A very interesting illustration of differential refraction on a large scale (which, in fact, is the 
only illustration the writer has ever seen on the subject outside of his own experiments) has 
recently been brought to his attention. This is found in Appendix 3, Vol. II, of Colonel Walker's 
report of the Great Trigonometrical Survey of India. Because of the inaccessibility of this report, 
the main facts on this point are here given. 



UNITED STATES AND MEXICAN BOUNDARY. 223 

The engineers were operating in a very level country, where the rays of light from the stations 
under observation grazed the surface of the ground. The dift'erential refraction was first noticed 
between two stations called Nilr and Jeto, the former being on a slightly elevated table-land 
between two river valleys, the latter being 13 miles distant in the valley bottom. It was feared 
that the ordinary heliotrope would not be visible, so a second heliotrope was mounted on a tripod 
about 10 feet vertically above the ordinary heliotrope. 

Colonel Walker says: 

The line between the instiiiment at Nar and the ordinary lieliotrope at .leto was not an air line at all, bnt 
passed through the ground for a distance of more than 3 miles, while the line between the instrument and the upper 
heliotiopo could not have been more than 5.3 feet above the ground at the point of nearest approach. At Jeto both 
the auxiliary and the ordinary heliotropes were generally visible for about an hour after sunrise and before sunset, 
but in the middle of the day the lower one was always invisible, being below the apparent horizon. Here I noticed 
with surprise, one evening, that the two heliotropes were apparently very much closer together than it was possible 
they could be in reality. Measuring the angle subtended I found it to be only Ki.o seconds, whereas the true subtense 
was 49..5 seconds. Three days afterwards, in the morning, about an hour after sunrise, I found the apparent subtense 
to be as much as 97.7 seconds. Thus its magnitude had varied from one-third to twice that of the true subtense, 
attaining a maximum value six times greater than its minimum value. This clearly showed that the amounts by 
which the rays of light proceeding from the two heliotropes were respectively affected by refraction must have 
varied materially at different hours of the day. The observations were only differential and did not give the ab.solute 
values of refraction, but it seems highly probable that the lower ray was very much more refracted th.an the upper 
in the evening and very much less in the morning. 

This remarkable phenomenon led to a systematic study of both absolute and differential 
refraction, the details of which are given in the volume mentioned. 

It will be sufiacient to state that numerous instances of negative as well as positive refraction 
were found, ranging between the extreme values of —0.09 and +1.21 of the contained arc. 
Negative refraction was met with only between the hours of 1 to 3..'10 ]). m., and positive retraction 
between 3.30 p. m and 10 a. m. After 10 a. m. signals were generally below the horizon, so no 
observations were possible. 

In the case of observations on dift'erential refraction it was found ''that the refraction was 
sometimes greater in the upjier ray and sometimes in the lower, but that the range from lowest to 
highest value at each station was always yr eater for the lower than for the higher ray. 

Between the hours of 1 and 3.30 p. m., whenever the sun was shining brightly, the apparent subtense was 
greater than the true and the refraction was lower in the lower ray than in the upper; but at the same time in 
cloudy weather the converse occasionally happened. On the other hand, between 3.30 p. m. and sunset the apparent 
subtense was always less than the true, and the refraction was higher in the lower ray than in the upper. These 
variations in subtense were evidently due to the coexistence of a lowering refractive power in the strata of the 
atmosphere nearest the ground with a raising refractive power in the strata immediately above during the hours 
when the radiation of the heat of the sun from the ground was considerable, and to the converse condition of a 
greater raising power in the lower than in the upper strata when there was little or no radiation and cousequestly 
greater density in the lower than in the upper strata of the atmosphere. 

• The application of the above record to the subject of .stadia measurements is easy to see, and 
it will be noted that the explanation given is essentially the same as that advanced by the writer, 
based upon observed stadia readings at diflereut hours of the day. The only dift'erence in the 
data is the relatively long distance of the sight from Nar to Jeto, it being 13 miles instead of the 
lew hundred feet which necessarily limit the length of a stadia reading. But even on so short a 
stadia sight as 1,000 feet the writer has seen the rod intercept change by 0.19 of a foot (equals 40 
seconds of arc) during different hours of the same day. Such large dift'erences in rod readings 
can be tinderstood when it is noted that if in the first case (see fig. IS) the upper line of sight be 
refracted negatively more than the lower, or if the upper line of sight be refracted negatively and 
the lower Hue of sight positively, then the observed intercept a' b' will be larger than the true 
in tercept a h. Again, if, as in fig. 19, the upper line of sight be refracted downward (positively) 
aiul the lower line of .sight upward (negatively) the observed intercept c' d' will be smaller than 
the true intercept c d. It will be seen that the difference in the observed rod readings, namely, 



224 



UNITED STATKS AND MEXICAN BOUNDARY. 



ft' h' (fig. IS) — c' d' (fig. 10) is iibout four times as large as any single refraction. Ileuce a small 
absolute refractiou may be the cause of a large differential refraction. 




A good illustration of this fact was recently sent tiie writer by one of the topographers of the 
Chicago Drainage Canal. The topographer was taking a stadia reading over a rise of ground 
wbeu he noticed that, in reading from the top of the rod downward the distance read was 127) feet, 




while in I'eadiug from a point near the ground upward the distance was shortened to 715 feet. 
For the reasons given above the former reading was more likely correct, though the manner in 
which the stadia interval was determined has a governing influence on this point. 



(A) KECORn OK EXPERIMENTS 



Table 2 
m. and 2.30 to 7- p. m., stadia mkasuhemkxts , 



■ 182*> iibiulo . 
.' 80°lllll<lo. 



} »» 

BodtlUUncti n 



. I "! jiAIrdiirty; littlo vibration . 

■CZ,;::::::::.!} -» 

(Ta-^itiiii ^ No Tilimtlon oven nt 2.000 ; 



Partly cloudy.. 



jSliglit vibrntiou; rod distinct . 

..I Very alight vibration 

.. Rodonniiotb»i-i}udart()r42Gm. 



loncuoh loDKtli alglit 

r of Hinitip nlgbt on oacb 



acli length night.. 
I length Blgiit 



■r:i 



'I '-"I '■''I 






I ..«.» 



'*>' I -"'" + ■'■ I 



l,839.0<m. I i.bm.nm. | 3, 9S0. 08 in. 3,411.Um. S.OlT.Mm. 3.S58. 



I I SLi; 



(fl) RECORD OF EXPERIMENTS FROM 9 A. M. TO 2.30 P. M., STAIJIA MEASUREMENTS AGOREGATINU 41.3 MILES. 



13ra.-lS.3 
2-3.30 p. n 






CZa. 
(»»"""■ 

lBO«.lmcl< 
rlOO ami . 
no°>liiulo 

ilOS'' auii 



:}•■•■"» ^ 

■ IVihrnOon of O.OIW at 122 m.. 



noe on (>Hi>h kngth siitlit 

irith MfU lensth >isbt 

of both MU. U) and iJt} 

Muiiim) with mch louglh jtlsht . 



S. Doc 247 To face] 



I 



Ll^lJlL 



'■": "■" ! 



1,»7 [ 0.73 I 17.< 



in« 




0.1) 





!.5. 




i.oa 






... 


m 











M) 






Erro 






otal 


300 feet. 


400 feet. 




91.45 m. 


11!1.938 m. 




+ 


_ 




- 








0.03 
.13 

1, 








0.24 











0.C6 
.01 
.01 
-.01 

.06 


.13 

.03 
.13 




























.06 


















.04 
.04 


.06 
.11 


.13 

.13 
.13 
.13 
1.10 






At 






0.00 


tAs 


n'o. 




- i.k. 


+ ,A. 




1,007. 40 in, 


1,219.38 m. 1 






0.16 
.16 
.16 
.16 


0.13 
.13 


0.16 





'h 




.16 














, 


















G3 






'"■" 




.16 
.16 


.13 
.13 






=5, 
















.03 






!iii 








.04 





.13 
.13 






ill 












.16 




.16 




,li 


0. 06 1 1. 28 


1.44 


0.90 




i,h 


,k 


^T 




oth 
(I 


-.1= 


+ I5'J5 


014«0ni. 


1,585. 19 III. 


1 


-lA. 


+ tA. 






2, Oil. 90 m. 


2,804.49111. 


3 


3 m 

63) 















UNITED STATES AND MEXICAN BOUNDAKY. 225 

(d) Effect of length of sight and hour of day on refraction. — A study of over 420 independent 
test stadia sights, aggregating 85 miles in lengtb, made on an accurately measured base line,* 
during tlie months of July and August, under the variety of conditions found in usual working 
Lours, gives undoubted proof of tliis refraction error. 

Table 2 is a record of the conditions of field work (such as date, time of day, temperature of 
air in sun and shade, the amount of sun and wind, and the unsteadiness of the air), aud the 
resulting acc-uracj' of sights ditteriiig in length from 00.77 meters (200 feet) to 009.084; meters 
(2,000 feet). 

This work naturally divides itself into two classes; first, stadia readings, varying from 00.97 
meters (200 feet) to 304.842 meters (1,000 feet) in length, made with full intervals; and, second, 
readings with half intervals, on distances varying from 335.320 meters (1,100 feet) to (!09.GS4 
meters (2,000 feet). For the purpose of a comparative study it has also seemed wise to divide all 
the work again into two divisions: (.4) Work done in the morning aiul evening hours (i. e., before 
9 a. ni. and after 2.30 p. m.) ; and (B) work done in the remainder of the day, 9 a. in. to 2.30 p. m. 

At the top of each column in the table is the true length of sight,t and the actual error of 
each siglit for that length is placed in the proper column witli proper sign (-|- or — ) indicated. 
A I the foot of each column this work is summed so as to show: (a) The "average error "J of a 
single sight of each length; [b) the sum of the distances of eacli set of observations on any 
distance; (c) the actual accumulated error for each of such summations. This treatment is 
repeated for work in both divisions of the day, and at the bottom of the table, division (7J), tlie 
two results are averaged together. A somewhat similar summation is made across the sheet from 
le!t to right. 

A study of these data discloses the significant fact that at all liours of the daj^, using the 
304.842 meters (1.000 feet) sight, both the average errors and the uncompensated errors greatly 
exceeded the errors existing when the sight was either 100 feet longer or 100 feet shorter. The 
reason for this is plain. The length of the stadia rod was such as to make it necessary in 
reading 304.84 meters to put the lower cross wire near the foot of the rod, and the lower line of 
sight sutfered an excessive refractioti compared with that of the upper line of sight. This 
excessive refraction in the cooler hours of the day resulted iu too large a rod reading, and during 
the middle hours of the day in too small a rod reading. When the sight was 100 feet shorter the 
lower line of sight rose above the stratum of maximum refraction, and a decreased difference in 
the amounts of refraction suffered by the two lines of sight resulted, giving a correspondingly 
decreased error. Again, the 335.320 meters sight was read by half intervals on the upper and 
clearer portions of the I'od. This allowed both lines of sight to traverse a nearly uniform stratum 
of air, thereby giving to each nearly equal amounts of refraction, and decreasing the error of this 
reading, compared with the one wliich was 100 feet shorter. It should also be noticed that the 
errors at 304 meters, 274 meters, aiul 243+ meters show a gradual decrease as the line of sight 
recedes from the ground. 

"This base line was measured with a carefully standardized 100-foot steel tape, and w.-is 2,216.888 meters 
(7,273.236 feet) long. The base was located on four streets, forming a quadrilateral, in the village of East Troy, 
Wis., about 20 miles from the Illinois boundary. The situation was selected for several reasons; first, it was over 
very level ground; second, the completion of a circuit left the observer right where he began, thus saving the lime 
which would otherwise have been required for walking to aud from work ; third, the four directions gave the 
average conditions of sun on rod met with in the field; fourth, on three of these streets the sun ahone .all d.ay 
uninterrupted by shade trees, while on the other, trees on either side partially shaded the ground. This furnished 
o|iportunity of observing the eft'ect of sun or shade alone, or alternate bells of both at the same time. 

The ground had been Ijrought nearly to true grade. Tacks were set iu stakes placed every 100 feet and lined 
in with transit. A spring b.alauco was used to measure the proper pull on the t.npe and the temperature of the air 
was recorded at frequent intervals. A scratch on the tack heads recorded each tape length. A line of levels was 
also run over the line, and the distance on each street computed, making the usual corrections for tape length and 
grade. As the assistant was a competent engineer, the precautions taken should insure an accuracy of not less than 
1/25000. 

t Determined by the base line m easurement. The writer has presented so much detailed evidence of differen- 
tial refraction and its effect upon stadia accuracy, because he believes this paper to be the first exposition of its 
quantitative measurement and application to stadia work. Itseemed but just, therefore, that the reader should be 
shown the d.ata upon which the conclusions .ire based. 

{Deduced from the recorded errors of 10 to 14 observ.ations. 



226 



UNITED STATES AND MEXICAN BOUNDARY. 



For coDvenience in comparison the totals of Table 2 have been brought together in Table 3. 
A glance at the individual sights recorded iu Table 2, or at the summations in Table 3, discloses 
the fact that in morning and evening work the bulk of the errors are positive (the readings are 
too large), while midday work with even greater uniformity shows negative errors (the readings 
are too small). The reason for this is that in the reduction of the field notes an average interval 
factor was used, as will be explained below. On account of the iulinence of refraction on such an 
interval determination, the average interval would be exact for only a small portion of the ticM 
day. Midday work computed with such an interval would give negative errors; while morning 
and evening work would, for the same reason, give positive errors. 

In Table 3 is shown the percentage of both positive and negative errors in each sei)arate class 
of work. Thus, in the morning and evening work, OG per cent of the errors were positive, 30 per 
cent negative, and 4 per cent were zero errors; while in the midday work this proportion was 
about reversed, i. e., 76 per cent of the errors were negative and 24 per cent positive. These 
proportions do not, however, correctly express the relative amounts of positive aud negative 
errors, for during morning and evening hours of work the negative errors are much smaller 
numerically than the positive eiTors, and vice versa during nudday hours of work. The actual 
amount of the positive error during morning and evening hours is 75 i)er cent of the total; while 
during midday hours the positive errors amount to but 4 per cent of the total error, though 
constituting 24 per cent of the whole number of errors. The reason for the small amount of 
positive aud large amount of negative ei-rors in work executed in the midday hours will appear 
in the discussion of the interval determiuation. 



Table 3. 
TTorl- done 7-9 a. m. and 2.S0-7 J), m. 



Short sights. 


Long sights. 


nis."^ 


S„™of 
distaucea. 


Accumu- 
lated error. 




.engthof 


Sum of 1 Acciimu- 
uistances. : lated error. 


Average 
error of 
singJo 
sight. 


Meiers. 


Meters. 


Meters. 




Meters. 


Meters. Meters. 




60.97 
91.45 


853.58 
1,097.40 


+0.51 
-0.07 




335.33 
365.81 


3,688.57 
4,755.53 


+ 1.55 
+ 3.35 




121. 94 


1. 219. 30 


+1.10 


.^. 


396.29 


3,902.94 


+ 4.12 


a. 


152. 42 


1, 829. 04 


—0.04 


tt'« 


426.78 


5,121.35 


+ 3.50 


tA, I 


182.91 


2,560.70 


+3.75 


oJ, 


457. 26 


4,115.37 


+ 0.40 


T^C 


2l:i. 39 


2,560.68 


+1.45 


I!>V. 


487.75 


5,852.98 


+ 0.16 


I^l 


243.87 
274. 36 
304.84 


3,414.24 
3, 017. 94 
3,658.10 


+0.20 
-0.02 
+0.64 




518. 23 
548. 72 
579. 20 
609.68 


.5,182.32 
6,035.89 
5,212.80 
5, 487. 15 


+ 7.49 
+ 3.30 
+ 2.68 
+ 1.85 












Slight. 

182 m. 


Total dis- 
tance. 

20,210.98 m. 


+7.52 


Average 


Average 
466 ra. 


Total dis- 
49,414.90 m. 


+ lAi 




oh 


(600 + feet.) 


(12.6 miles.) 






(1,528 + feet.) 


(30.9 miles.) 






(6 zero erro 


rs, 6 per cen 


t. 






t. 


Ill sig 


1113^69 plus er 


ors, 62 per c 


ent. 


106 .sig 


itsm plus errors, 70 per c 


3nt. 




|36miuu.,e 


rrors,32per 


.•ont. 




[m minus errors, 28 per 


cent. 



n43 
tsJeo I 



) errors, 4 per cent. 



UNITED STATES AND MEXICAN BOUNDARY. 

Tablk 3— Coutimied. 

Work done 9 a. m.-3.30 p. m. 



227 





Short sights. 




Loug sights. 


Length of 
sight. 


Sum of Accumn- 
distances. | lated error 


Average 
error of 


Length of 
sight. 


Sum of 
dUiaiices. 


lated error 


Average 

IS? 


Meters. 


Meters. Meters. 




Meters. 


Meiers. 


Meters. 




60.97 


. 792.61 -(- 0.U7 


I0>5, 


335. 33 


3,688.57 


— 8.89 


jIe 


91.45 


914.50 - 1.22 


^■, 


365.81 


4.7.'>.i.53 


— 20. 96 


jSb. 


121.94 


1,585.19 1- 0.54 


oh 


396. 29 


3, 566. 64 


-16.93 


.Ij 


152.42 


1,371.81 —1.53 


»5t 


426. 78 


5, 548. 13 


— 26. 09 


lib 


182. 91 


2,194.88 H 2.79 


,h 


457. 26 


5, 029. 89 


— 18. 65 




213.39 
243.87 


2,133.90 ! —3.00 
2, 926. 49 < — 2. 29 




487. 75 
518.23 


5,8.12.98 
4,664.09 


— 30.43 

— 21. 58 




274.36 


2, 469. 22 — 7. 30 


zhs 


548. 72 


6,035.89 


— 29. 49 




304.84 


3,962.95 


—16.01 


= h 


579.20 


4,054.40 


— 23. 74 


I-I 










609. 68 


4.877.47 -33.03 


as 










Average 
length of 


Total dia- 
tauce. 


—28.01 




Average 

length "of 

sight. 


Total dis- 
tance. 


-229.78 




182 + m 


18,351.53 ni. 


— eh 


,1, 


462 + m. 


48,073.60 m. 


- ,u 


^T 


(600 + feet.) 


(11.4 miles.) 






(1,515 + feet.) 


(30 miles.) 






101 «ig 


(61 minus errors, 60 per 


cent, 
nt. 


104sights{^f"'«™'«^'«'^ 
* l8 plus errors, 8 per cen 


cent. 



... . , „ . . , fl57 minus errors, 77 per cent. 
Tot.-ll: 20,. sights , ' 

Us plus errors, 23 per cent. 

[191 plus errors, 45 per cent; but 13 per cent of total .tnioiint of error. 
Summation: 422 sight8<223 minus errors, 53 percent; but 87 percent of total amount of error. 
[s zero errors, 2 per cent. 

In the column of Table 3 headed "Average error of single sights" may be found what is 
really th" average error (or the probable error) of the readings at difiereut distances. An average 
error* of each class of work is found by dividing the average error of a single sight by the 
average length of sight. Thus, in morning and evening work, using short sights (200 to 1,000 feet), 
tiie average sight was 182.9 meters ((>00 feet),t and the average error of a single sight was the total 
error (18.56 meters), divided by the number of sights (111) or 0.167 meters; and 0.1(i7/182.9=l/109r), 
which is the average error of the average length sight. Using long siglits (1,100 to 2,000 feet), the 
work done in the same morning and evening hours shows an average error of a single sight of 
1 935 (average length of sight 166 meters, or 1,528 feet). The average error of an average length 
sight on work done in midday shows a marked increase, as compared with the rest of the day. 
Thus, on short sights it is 1/132, and on long sights 1/201. 



* This average error corresponds to the probable errors of observation on an unknown length, bnt, as in this 
case, the real distance i.s known, the average error Is more triistworty than any probable error computed on alimited 
number of observations. 

tThe United States official relation between standard measures is 1 foot^O.304801 meter. 



228 



UNITED STATES AND MEXICAN BOUNDARY. 



r 






















moo 
1 




( \ 








Law. 


X= Length of sig.'t. 
Y- Average accuracy of 
each ^ength si iht. 




1600 

7 




1 \ 
1 , 




1 














1400 
1 


1 ^ 


H 


""^vJL 


1 

\ 

1 


1 \ 






.A. 




1200 
1 




J 1 


/ 


1 
\ 


1 \ 


1 


:1 / 


\ 
\ 

\ 

\ 

, \ 




WOO 

1 






/ 


K^ 


1 ^ 


1 f 




\ ; 


^ 

^>i 


800 
1 






/ 






\ 
\ / 










600 

t 














! 

j- 






400 
20 


40 


(7 fC 


70 80 


IOC 


70 m 


70 14 


10 mo 1800 aooo'^u. \ 



Fic. ;u.-Krror rurvn Icir inoniiiig and evening work, 217 test siglits: 43.5 miles. 

Till' inaiiner in wliicli the average error of a single observation is aft'ectcd by tlic Iciifjtb of 
sight i.s s1k)\vii by tlie (u.rves in figs. 20 and 21. In both curves tlie x coordinates arc the lcni;tlis 
of sight exi)rcsscd in feet, while the y ccoi-dinates represent the average errors of the readings of 



Y 

1 






















1000 


V 


.a 


















800 

1 


\ , 


H 


^ 
















600 

1 








\ 














400 
1 










/ 1 




fc^ 


^JK^ 








200 












■ 








^ 


X 


ZOO 400 600 eoo woo /zoo 


1400 1600 /aoo 


ZOOOFeET. 1 



Tin. 21.— Erriir curve for iniilday w 
Bifilits of 200-2,000 feel in lensMi. 
East Troy, Wis., 1894. X ami Y 



S.30 p. m.), 204 test sights, aggregating 41.3 miles, on a base line, using 
in fig. 20. 



UNITED STATES AND MEXICAN BOUNDARY. 



229 



the different leiigtlis (10-1-t observatious each). The coordinates of the heavy regular curve are 
siniihir except that the ordinates represent the averages of the three adjacent ordiuates of tlie 
broken curve, hence it is an average curve. It will be seen that this regular curve (lig. 20), 
representing results of work in the morning and evening hours, does not vary widely from an 
accuracy of 1/1000, even on the very long sights; while the marked irregularities of the corre- 
sponding broken curve indicate the presence of the usiial accidental errors of observation, first 
jiositive and then negative. 

Summation of results. 



Time. 


Short siglita. 


Long sights. 


Total. 


Morn ing and evening work . 


Average error single sight o 

miles= + „'„. 
Average error single sight o 

miles = -^,. 


a 12.6 
u 11.4 


Average error single sight ou 30.9 

miles = + ^^. 
Average error single sight on 30 

miles = -jJ,. 


43.5 miles + „W 




'" 



The curve (flg. 21) represents the errors of work done in the middle of the day, and is in strik- 
ing contrast to iig. 20; for, during the first half of its length, the error curve descends quite rapidly 
and uniformly from an error of 1/1029 at 200 feet to 1 210 at 1,000 feet, from which last point the 
curve desceuds very much more slowly to the longest sight (2,000 feet). The rapid descent in the 
first half of the curve is due principally to the increasing differential refraction, as the lower line 
of sight approaches the ground, as has been i^reviously explained. The rapid descent of the curve 
is arrested at the 1,100-foot point, because the reading of the remaining distances (1,100-2,000 
feet) by half intervals, r.aised the lower line of sight out of the stratum of maximum refraction. 
In fact, the upward movement of both lines of sight jjut both in strata of nearly eipial refracting 
power, and the rod intercept was, accordingly, subject to less error. But after 1,800 feet the 
lower Hue of sight was again forced into the maximum refracting stratum, and the curve takes an 
increased descent as a result. 

The fact that such large errors result from a lack of uniformity in the amount of refraction of 
light rays, when obliged to traverse strata of different densities, suggests the advantage of placing 
the stadia rod in a horizontal position instead of in a vertical position when making a reading 
for distance. The practical difficulties of such a method, Avhile great, are perhaps not insur- 
mountable.* 

(e) Effect of refraction on accumulating errors, — Not less interesting is the manner in which 
the errors of these 85 miles of measurements accumulated. Twelve miles of stadia measurements, 
made with short sights (average length 600 feet), in the mornlny and cvenuuj hoars, show an 
accuracy of + l/2r)S5, while the same distance, measured by sights of the same length in midday, 
show an accuracy of but — l/OS."). Again, 30 miles of measurements made in the morning and 
evening hours, using long sights (1,100-2,000 feet), show an accumulated error of but -f 1/741, 
while the same distance, measured in the same way but in midday hours, developed an accumu- 
lated error of— 1 209. 

The practical deductions to be made from this work are therefore, first, do not attempt 
accurate stadia work in hours not represented in your interval determination; and, second, in 
midday do not make long readings which require the lower stadia wire to be put nearer than 3 or 
4 feet from the bottom of the rod. If such long readings can not be avoidetl, take the readings 
by half intervals on the upper and clearer portions of the rod. If this method had been followed 
in the work shown in table 3, the resulting accuracy of the work would have been greatly 
increased. Thus the accumulated eri'or in 12.0 miles, measured bj' short sights (average length 
182 meters, or 000 feet), iu morning and evening hours, is + 7.52 meters, while that of the midday 
work, oaiitting the 900 and 1,000 feet sights, is — 4.70 meters in a distance of 7.4 miles. The 
accumulated error of the total measurement (20 miles) is + 2.82 or -f 1/11,400. That such a nice 
balancing of errors is always possible in actual field work, the writer does not for a moment 



' The writer lias i 
. later. 



eiitly begun a series of experimeuts, using this method, the results of which may be jjub- 



230 UNITED STATES AND MEXICAN BOUNDARY. 

supi)ose; but that a careful planning of auy jiroposed liekl work will give results far superior to 
those obtained without such study seems too apparent to ueed further discussion. 

Unfortunately for tlie interests of the stadia method, the ett'ect of refraction in producing 
accumulative errors and the proper methods for preventing such errors are only partially 
appreciated or understood by stadia engineers. For instance, one prominent engineer of wide 
experience with the stadia argues that the best time for determining the stadia interval is during 
the middle of the day. He bases his reasoning on two well-known facts: First, that during the 
middle hours of the day the atmospheric refraction of light rays is at a minimum, and he cites 
many authentic cases on record where this was the observed fact; second, that during the middle 
hours of the day the amount of refraction changes but slowly, while at morning and evening this 
change is rapid. This engineer makes an error, however, because he is treating his patient for 
the wrong disease — for absohite refraction instead of differential refraction. It would be just as 
sensible for the physician to give the usual remedies for pneumonia to a patient suffering from 
consumption. Tliis is not quibbling over a name, but it is a serious question of the proper remedy. 
In the present case the wrong name for the disease has determined the wrong remedy, and 
therefore the name is important. 

IV. The Proper Rkmedy for Systematic Errors. 

(a) The correct statement of the problem. — The error of the engineer referred to above is such a 
common and natural oue that it is worth while to make it perfectly evident. In making a stadia 
reading you are concerned with the relative behavior of two lines of sight which traverse widely 
diverging portions of the atmosphere; while in making any other kind of pointing, as in reading 
a vertical angle on a distant signal, you are concerned with the behavior of but one line of sight. 
Conditions which may cause a minimum amount of refraction for such a single line of sight may 
or may not be such as to cause a minimum difference of refraction in a stadia reading. They are 
quite independent phenomena, and there is no simple relation between the two cases. In the first 
case an observer is concerned with the absolute refraction of a ray of light passing through the 
air, and it is known tliat the refraction increases with the density of the air— i. e., refraction varies 
inversely with the temperature.* In the second case the observer is concerned, not with tbe 
absolute amount of refraction, but with the relative amounts suffered by the two lines of sight. 
Obviously, that condition will be tlie best for stadia observations which causes both lines of sight 
to be bent either not at all, or bent the same amount in the same direction. As far as refraction 
affects the accuracy of stadia work, one of these conditions is as favorable as the other. Now, it 
happens that during the middle of the day, 10.30 a. m. to 2 p. m., the absolute refraction of light 
rays is small and changes but little, but the differential refraction during this time is excessive, 
as has been shown experimentally; moreover, it is well known that during these midday hours 
"seeing conditions" are very unfavorable to accurate work. The rod appears both unsteady and 
indistinct, giving large accidental errors.! The argument, then, that the middle of the day is the 
best time for determining the stadia interval, even without experimental i)roof to the contrary, is 
at best a mere assumption ; and in the light of that proof the assumption is shown to be false. 

If an engineer determines his interval under the conditions which obtain in midday, condi- 
tions which are the very farthest removed from the average conditions of the working day, his 
work done during midday would certainly be expected to be more accurate than that done during 
the remainder of the day. But unless he intends to confine his work exclusively to midday, which 
is of course absurd, he would be inviting systematic errors by choosing midday for the interval 
determination. 

" This branch of the subject has been very carefully studied by the United States Coast and Geodetic Survey. 
See reports of same for 1871, pp. 154-170; 1876, pp. 355-367; 1883, pp. 281-321; 1884, pp. 391-405. The minimum 
amount of absolute refraction comes at about 3 p. m., the hour of higliest temperature, and the maximum amount of 
absolute refraction comes twelve hours later, with the lowest temperature. 

t In the tield work of the Mexican Houndary Survey accurate stadia measurements were not attempted iluring- 
the middle of the day, if the unsteadiness was marked, and in the more desert region accurate work was sometimes 
suspended from 8 a. m. to 3 p. m. During such time work was done on side lines, in " tilling in " togography, where 
there was little chance for accumulating errors. 



UNITED STATES AND MEXICAN BOUNDARY. 231 

{h) The case applied to the recent survey of St Louis. — That this is not mere theorizing will be 
abundantly proved by a glance at the results of the recent survey of St. Louis, a survey 
which, in most respects, is the equal of any municipal survey of recent times. The report* of this 
survey states that "stadia distances were always read too long; that of the hundreds of stadia 
lines run, the coordinates of whose stations are upon record, there is not a single exception to the 
fact that, in lines run north and south, the latitude is always more in error than the longitude, 
and that, in lines run east and west, the longitude is always more in error than the latitude." The 
report also gives a tabulation of a stadia line run around the city, the length of which was 40.4 
miles, and which frequently was checked on triangulation stations. Near the southern-most 
point, 22 miles from the beginning point, the errors had accumulated to +38 meters in latitude, 
+ 14 meters in longitude, or +1 877; but when the line had returned to the point of beginning, 
the constant error, continuing, canceled itself, so that the closing error of the circuit was 1/6332. 
These, and other facts, prove that distances on this survey were always over-read t 

In order to understand the reason for the systematic errors it will only be necessary to inquire 
into the method of the interval determination. The engineer in charge gives out the following 
facts: The interval of the single transit used in the stadia work was determined by a single 
observer, and was made to depend upon ten observations taken at some certain half-hour (not 
recorded) of a July day, over ground and in weather that are admitted to differ widely from the 
average conditions met during the three years of Held work. As previously stated, the engineer 
in charge states in his report that the proper time to determine the interval is in the middle of 
the day, so that it is safe to assume that in his work he followed his own advice. 

The experiments discussed in this pajjcr show that in the hot months, at least iu July and 
August, the intercept on a stadia rod reaches a minimum at about 11 o'clock a. m., and changes 
very slowly for several hours. This small rod intercept would result in too large a stadia interval. 

That is, iu the common formula D=K«, the value of K=( — \ determined by midday observations 

would be too large, since the observed values of *• would be the minimum instead of the average 
for the field hours. It would, therefore, be expected that measurements covering the usual field 
hours of every month in the year should be excessive. Such was actually the case at St. Louis.f 
(c) The accurate waij of detcrminimi the interval. — Had the stadia interval been determined 
early iu the day or late in the afternoon, the results would have still shown systematic errors, but 
of opposite sign. However, had the interval determination extended over all of the field hours of 
several days so as to get average conditions, such systematic errors would have been changed into 
compensating ones, and the longer the line the greater would be its relative accuracy. Even in 
this case, as a matter of caution, it would be wise to redetermine the interval whenever the 
conditions of field work had, for any reason, become greatly different from those attending the 
original interval determination, e. g., an interval determined in the hot summer months should 
not be used in the cold winter months without testing it by another independent determination. 
In every such determination let every condition affecting it be, as near as may be, ecpial to the 
average conditions to be met in the field. If the survey is to be over ordinary soil, do not 
determine the interval on a stone curbing; if the rodmau is not to be aided by a plumb bob in the 
field, do not sufter such aids in holding the rod for the determination, and above all let each man 

* See Journal of the Association of Eugiu(-ering Societies, A'ol. Xll, p. 1. 

t Because of this fact the cugiueer, in his report, advises setting the transit 43 centimeters back of the initial 
point on the base line, in determining the stadia interval, so as to virtually subtract that amount from each rod 
reading. While this would be correct in his work it certainly would not be correct when generally applied to stadia 
work. For instance, the engineer in charge of the stadia survey of the Chicago Drainage Canal, the surveys of 
which already cover 50 square miles, states that all his stadia distances, as compared with those obtained by steel 
tape and triangulation, show a minus error (too short) of about one-half the amount on the former work. In the 
writers's own experience, the measurement on the Mexican boundary line, of 45 miles of level mesa, across that 
part of the Yuma Desert between the Colorado River and the Tiuajas Altas Mountains, showed a minus error of 3'J 
meters as compared with the triangulation determination of the same distance. In short, whether the accumulated 
errors are positive or negative depends almost entirely on the method of interval determination, and especially upon 
the hours of day used in such interval determination. This point is made clear in the following discussion. 

t Experiments made the jiast winter iiidicale that rod readings made in the middle hours of a winter day are 
much greater than those made in the corresponding hours of summer d.ays. This fact, if it proves to be true, would 
cause all winter work of the St. Louis survey to show positive systematic errors. 



232 



UNITED STATES AND MEXICAN BOUNDARY. 



.10 

.so 

.60 
.70 
.60 
SO 
.40 
/0S.30 




Y 


















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y 
















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Showiug the n 
uly 8-U, 18113. 
gtii of si-hts i: 



f Brandis Trausit, 
California, 
sponding inter^-nl. 



who i.s lo nav ;i tniiisit (leteimiiie an interval fm- his own use. In this way liis personal eiiuation 
will be eiiniinatecl. A careful examination of the held records of twenty-four interval determina- 
tions made on the Internatioual Bouiulary Survey proves conclusively the truth of the above 
statement. A few of the typical curves of the.^e intervals may be of interest. 

Fig. 22 represents two stadia interval deter- 
minations made at Nacho Guero Valley, Lower 
Califoniia, during consecutive days and on the 
same base line with same instruments, rod, and 
observers. One interval was taken during tlie 
hours G to 7.30 a. m., the other Irom 4 to 5.30 p. m. 
Unfortunately the notes do not record which was 
morning and which afternoon, but the full line 
curve closely resembles the normal afternoon curve. 
The first thing to note is that the average ordi- 
nate [100.76] in curve («), namely, the average value 
of K differs from that of curve {/>) [100.55] by 1/500. 
The interval used until this time was 106.98, which 
differs from («) by 1/-1SC, and from [b] by 1/250. 
The writer believes this to be a very unusual dis- 
agreement, and one explained by the position of 
baseline, which lay along a small valley with trees 
so distributed that the line of sight traversed alternate strips of sun and shade, the former largely 
]n-edomiuating. An abnormal lefraction resulted, causing both determinations to differ widely 
from the average of several previous ones. 

The extremes in temperature at this place in early morning and afternoon were very 
pronounced. Ice would nearly form in morning, while during the afternoon the temperature would 
rise to 98° J<\ The result of such a marked difference in conditions explains the large difference 
in the resulting intervals. The fact that the choice of an improperly located base line could cause 
so large an accumulative error as 1 486 would seem 
to justify more care in such selection than topog- 
raphers have been accustomed to think necessary. 
The point that should not be lost sight of in 
selecting the base line is that condition of soil, 
vegetation, etc., shall not differ widely from the 
corresponding conditions expected in the field. 

The necessity of testing for a change of inter 
val with a decided change in season is emphasi/i d 
by fig. 23. Curves a and h represent respectively 
the interval determinations of March 20 and July 
10, 1893, of Brandis transit No. 1573, made at same 
morning hour. It will be seen that botli curves 
are parallel to axis of X for a considerable dis- 
tance, but on sights greater than 200 meteis the 
platted ordiuates [values of K] differ widely and 
systematically, as is seen by the rapidly diverging 
curves. The average value of the ordiuates in 
curve a is 106.85, while that of curve h is 106.53. 
average conditions of winter and the latter of summer, a systematic error of 1/333 would be made 
in all stadia measurements executed during the summer by continuing the use of the winter value 
of K instead of its actual or true value at such a time. 

In view of this proof of the inevitable change in the value of the interval, th common 
practice of painting a rod to correspond with the stadia interval of a certain hour and day and 
then continuing the use of such rod unchecked and unchanged during the widely different seasons 
of this country — oftentimes, in fact, for many years at a time— is seen to be inviting the large 
systematic error which almost without exception characterizes such work. If this evidence be 





r 


' 




r 






1 — 


^ 


II 




^ a 


.90 
.BO 
.70 
.60 
SO 
.40 
.30 
10620 














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fro. 23.— Slio 
X = length 



That is, if the former value represented the 



UNITED STATES AND MEXICAN BOUNDARY. 



233 



taken to prove the fact that even so-called fixed stadia wires actually change their relative 
positions, or, what amoauts to the same thing, appear to change on account of the influence of 
differential refraction at different seasons, then the present method of painting the rod to 
correspond with the dctermiued interval is objectionable because of the cost of regraduating and 
repainting the rod to correspond to such change in interval. A method entirely free from this 
objection of cost, and one which the writer has found to stand every test during several years of 
field use, is that which uses rods divided into true units of feet, yards, or meters and employs 
an interval factor in the computation of distances. With this system a change in the interval 
simi^ly means the loss of an hour's time in the preparation of a new table for reduced or true 
distances corresponding to any rod reading. 

Eew experienced topogra]ihers will deny the ftict that many observers have a decided personal 
ecjuation* in reading a stadia rod. The more experienced the observer the more pronounced the 
personal equation. It seems to be due to a bias of judgment in making the bisections and in 
estimating the position of center of stadia wire. The following fact will illustrate this point: On 
the International Boundary Survey each transit man was instructed to observe the interval of 
his transit in conjunction with one other engineer.t An examination of the field notes discovers 
that some engineers had the same personal equation, while others differed quite radically, as is 
seen in the following table of the first four interval determinations of Brandis transit No. 1584: 

Brandts transit, 15S4. 



Date. 


Interval deter- 
mined by- 


Number of 
transit. 


Mr. S. 


Mr.O. 




104.61 

104.82 


104.57 
104. 61 


B. No. 1584 
B. No. 1584 
B. No. 1584 
B. No. 1584 




Aiiiil29 




104.51 1 104.41 


^ 


104 69 1 1IU V^ 


Difr.== 1-750 









This transit measured the boundary line from El Paso to the Colorado Kiver. Opposite each 
date will be found the separate interval determined by each of the two observers. It will be seen 
that all of Mr. O.'s deteiniination of K are, without exception, smaller than the writer's, and that 
the average discrepancy would c;iuse an accumulative error in measuring 1,040 feet of 1.4 feet, or 
of 1 in 750. The size of this error, though serious enough, is not so objectionable as the fact that 
from its nature it must be systematic. The custom of having the chief of the party determine the 
working value of the interval, while his assistants do the observing, is thus seen to be wrong in 
both theory and practice. The better way would be to let the user of the transit determine the 
stadia interval himself, or if several engineers were using the same instrument let each determine 
his own interval. 

An example of the case of two observers with very much smaller diff'erence in personal 
equations is seen in the following table, taken from the records of the same survey : 



Date. 


Locality. 


Interval deter- 
mined by— 


Number of 
transit. 


Mr.S. 


Mr.C. 


July 26, 1892... 
Jan. 18,1893... 




104.62 
97.59 
104.53 
106. 88 


104.57 
97.50 
104.47 
106. 77 


B. No. 1586 
B. No. 1097 
B. No. 1584 
B. No. 1573 


Timia Ariz 


do 




d : : ::":::::;::::::;:: 






103. 40 


103. 34 


Dif.= 1-1722 


^ 



* The engineer in charge of the St. Louis survey states that "there was a higher degree of accuracy noticed 
in the stadia work of the engineer who determined the wire interval;" also, that "a uniform difference in the 
accuracy of work done by the several observers was shown by the computation of the coordiuatesof stadiastations," 
thus indicating a different personal equation for each observer. It should be noted that only the experienced 
observer can be said to have a personal equation, and this personal eciuation would be more and more constant and 
important with increasiuy experience. 

t In computing the average or working interval on this survey double weight was given to the observer who 
used the transit. Doubling the number of observers doubled the time necessary for the determination without any 
compeusatory gain in accuracy. For this reason a single observer is preferable. 

S. Doc. 257 19 " 



234 



UNITED STATES AND MEXICAN BOUNDARY. 




Ill tbis case, as in tlie oue given 
above, tbe ditterence between the ob- 
served intervals is seen to have a constant 
sign, name]}', each of Mr. C.'s values are 
less than the writer's, though the difler- 

Ailr'i'ri'il'Vss" ence is small, being 1 in 1,722. 

4.30-6 p.m. rpjjg ]nf^i^ ijut |jy jiQ means the least, 

potent cause of systematic error in the sta- 
dia measurement of the Mexican bound- 
ary line remains to be discussed; but first 
a few words of explanation. 

If, in determining the stadia interval, 
the transit bo centered a distance f+c 
back of the zero of the base line (see flg. 
18), the angle formed by the upper and 
lower line of sight, constituting the stadia 
reading, will have its apex directly above 
the zero of the base line. Xow, if it were 
not for the influence of differential refrac- 
tion, the intercept on the stadia rod held 
at any i)Oint on the base line ought to be 
proportional to the distance fiom the rod 
to the zero of base line. In other words, 
if we substitute in the usual stadia for- 
mula D=KS, the several rod readings Si, 
Si, S:„ etc., and also the (jorresponding ex- 
actly determined base-line distauces to 
the rod, I),, D,, D3, etc., we will have an 
equal number of observation ecjuations 
Ta3. containing only one unknown (piantity, 
namely, K, the stadia interval, and solv- 
ing for K we should expect a series of 
values att'ccted only by accidental errors. 
So much lor theory. When put in prac- 
tice this method almost invariably gives 
a series of values of K difl'ering system- 
atically from each other, the best possi- 
ble proof of the existence of difierential 
refraction. Obviously this disturbing 
agency is the factor which determines the 
accuracy of stadia measurements. 

The graphical method is well adapted 
for bringing out more clearly this point. 
If a curve be constructed whose abscissie 
are the lengths of sight [varying from 80 
meters to 400 meters], as determined by 
the baseline measureuieiits, and whose 
on. sept.is, ordinates are the c()rres])onding values of 
K, as determined above, such a curve 
should be theoretically a straight line par 
allel to the axis of X. Instead, with rare 
exception, it is found to be a curve cutting 
the axis of X. An illustration of this fact 
will be seen in the curves shown in fig. 24, 
and which represent all the interval de- 
terminations of Brandis transit No. 1584. 



of Braiidis S 1584. 



UNITED STATES AND MEXICAN llOUNDARY. 



235 



Iti the interval (leteiiiiinatious, made in tlie alteinoon, it will be noted that the valiie.s of K 
decrease quite uniformly as the length of sight on the base line increases, shown by the descending 
curve; while in the morning determinations just the opposite is true— i. e., the values of the 
interval increase with iu(!reased length of sight oii base line, shown by the ascending curves. 

As a rule, the extreme values of K (i. e., those determined at the 80 and 400 meter distance) 
will be found to difl'er greatly, as, for example, in one case, 1 in 174 (see curve 2, tig 24). Now the 
working conditions from El Paso to Yuma were such, that the average length of sight on this 
section of the boundary line was 21.5 meters and of the 4,000 stadia sights along this 540 miles of 
line less than 10 per cent were of more than 270 meters in length. But, as stated in the report of 
Mr. J. L. Van Ormnum, assistant engineer, the method of finding the true or working value of the 
interval was to take the average of all the individual values constituting a deterrainatiou including 
those from SO to 400 meters. On account of the systematic ditterences in these intervals this 
method would be correct only in case the stadia readings of the field measurements were approxi- 
mately equally distributed over the same range in distance as those of the interval determination, 

A good illustration of this point is found in the stadia measurements, between monuments, 
along the boundary line from jMonument No. 43 to Monument No. (W>. Nineteen of these measure- 
ments were afterwards checked by a triangulation and by careful steel tape measurements with 
the result shown in the following table: 



Between moimmeDts. L\ sTstadia. 


Tliailgi.la- 

tiou an<T steel 

tape. 


Error of 
stadia. 


K = 101.44 
U.S. stadia. 


Error of 
stadia. 




2leters. 
3,691.74 
4,779.95 
4,445.93 
4,399.24 
5, 793. 63 
3, 340. 28 
3,332.65 


Mtler.. 
3, 690. 14 
4,773.91 
4,443 17 
4,382.20 
5,774.95 
3,334.02 
3, 324. 18 


Meters. 
+ 1.60 
+ 6.04 
+ 2.76 
+ 17.04 
+ 18.68 
+ 6.20 
■i 8.47 
+ 4.66 

J_ 7 OS 


Meiers. Metirt. 
3,686.10 —4.04 
4,772.70 — 1.21 
4 439 4 17 


46- 47 




49- 50 

60- 61 


4, 392. 60 
5,784.70 
3, 335. 20 
3, 327. .M 
5,983.0 
6,058.4 
6, 322. 9 
6, 688. IS 

5, 690. 10 
4,4.58.4 
3,305.4 
3,473.17 
3, 070. 18 
3, 622. 3 
1,528.0 
2,471.70 


-HO. 25 
-f 1.18 
+ 3.32 

— 4.53 
-2.02 

— 2.61 
-1- 3.00 
-3.25 

— 4.18 

— 3.47 

— 1.90 

— 3.43 

— 1.64 
-t 0.67 
+ 0.39 


69-70 


83 84 


6 067 07 i 6 060 4'' 




0,332.40 fi.325.51 -|- 0.89 
6 698 31 ■ 6 685 la : 4. 13 13 


87 88 




5, 698. 71 
4, 465. 20 
3,310.40 
3 478.41 




92- 93 


4,402.58 
3, 308. 87 
3.475.07 
3, 073. 61 
3, 623. 94 
1, 527. 33 
2,471.31 


+ 1.53 

+ ^-'^ 
-f 1.24 
+ 3.84 
+ 2.94 
+ 4.11 




94- 95 


95- 96 


3,074.85 
3, 027. 78 
1,530.27 
2,474.42 


107-103 






Total 


■ 82,535.(53 


82,417.27 


+ 117.70 


82,409.23 


— 8.04 



It will be noticed in this table that every one of the 19 checks shows a systematic error — i. e., 
every one of these stadia measurements was too long, the average error being 1 in 700. This 
shows that the interval factor (K), used in the computation of distances, was too large. This 
value of K was 104.(50. As the stadia sights of the field measurements were practically limited to 
those less than 270 meters in length, the computation of the interval should have been restricted 
to the same limit of sight on the base line.* Had this been done, the resulting value of K would 
have been 104.44. 



'In oxplan.ation of why this method was not employed, it should be stated that at the time the field work 
was done the causes of systematic errors in stadia measurements were nowhere thoroughly understood. A careful 
study of methods and results of topographic surveys made in the Tlnitcd States and elsewhere convinces the writer 
that the held methods used in the toposjiaphic work of the United .States Boundary Survey were the most carefully 



and judiciously planned and executed of any toiiographi' 



ith which he is acur 



itcd. 



236 



UNITED STATES AND MEXICAN BOUNDARY. 



Computed with this value of K, the distance between monuments given in Table 4 would have 
been less by 1 in (550. In the last two columns of Table 4 will be found each separate distance 
between monuments computed on this basis, and also the resultiuj,' error (with proper sign) of the 
determination. It is interesting to note that, unlike the first set of errors, these latter errors are 
not systematic, and that their absolute values, wiMi only four exceptions, are less tlian the actual 
errors computed with the adopted interval (104.00); and finally that the accumulated error of 
these 82,417 meters of stadia measurement is only 8 meters, or an error of 1 in 10,(tOO, instead of 
tlie original 117.76 meters of error (1 in 700). Nor is this explanation true of only the interval 
under discussion. A glance at fig. 24 will show that the same reasoning applies equally well to 
all the other morning determinations of transit 1584, and the writer will add that it also applies 
to 13 out of 15 morning determinations of other transits used on the survey.* 

Of the 24 interval determinations made on this survey only three were made in the afternoon, 
although as many measurements were made in the afternoon as forenoon. This fact in itself may 
have been one cause of the systematic error shown in Table 4, a^ experience shows that the values 
of the interval determined in the afternoon arc less than the corresponding values determined in 
the morning. This fact is illustrated by fig. 25, which shows 2 curves, the upper being the 





BO IZO 160 ZOO 140 ZeO 3Z0 3 


SO 400 Metkes. \ 


104.70 
.60 
■SO 
.40 
.30 

104.20 




















A.M.CUK\^ 






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rm. 25.— Showing characteristic interval < 



5 of morning and afternoon. 



average curve of the four morning intervals shown in fig. 24, while the lower curve is the average 
of the only two afternoon determinations (shown in same figure). A glance will show that the 
average ordinate of the morning curve — i. e., the average value of the interval factor — is larger 
than that of the afternoon curve. That is, distances computed with afternoon intervals would be 
shorter than if computed with morning intervals. 

From the foregoing data this generalization can be drawn : Test the stadia interval only on 
distances and at hours that will he /re(piently employed in the field measurements. In the class of 
surveys the writer has in mind, viz, those extending over a considerable length of time, this 
caution can easily be employed. 



*The two exceptions noted above furnish internal eviilence of being abnormal, 
that the determination was entirely disregarded by the Commissiou. 



In one case this was so clear 



UNITED STATES AND MEXICAN BOUNDARY. 



237 



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238 UNITED STATES AND MEXICAN BOUNDARY. 

((7) Experimental work showing the compensation of errors. — In order to discover to wliat extent 
errors wonld acemnulate, in making a long stadia measurement under actual field conditions, 
thirteen independent stadia measurements of the base line* were made on the several days and 
under the conditions of weather and length of sight recorded in Table 5. The method adopted in 
making these measurements insured the determinations of each distance being entirely independent 
of any knowledge of what such readings should be. In nearly every sight the transit was set ui) 
at undetermined points on the line, so that though the rod was always held on the hundred-foot 
stations its distance from the transit could never be known by the observer. Moreover, the rod 
was graduated in meters and the base line in feet. As only one rod of the kind adopted was 
available, only a single stadia line was in any case measured. There can be no doubt that the 
accuracy actually obtained could have been improved by taking botii a foresight and a backsight 
on each distance, but with one rodmanf this wasted too much time in walking. When the wind 
blew the rod was provided with a plumb line for aid in holding the rod plumb. 

Table 5 is a record of the conditions affecting the work and the results of tlie work. This 
record includes («) the actual error made on each street, expressed in meters; {h) the corresponding 
fractional error of each street measurement, and of each complete circuitf of 2,21(».8.S8 meters; 
(c) each circuit is also summed up from the beginning, and the corresponding accumulated error 
is given. This varies from 1 2091 on the first circuit to 1/10404 at the end of the thirteenth circuit. 

Of the thirteen measurements given in the table, 8 were in the forenoon and 5 in the afternoon, 
and the work covered ev^ry hour of the day from 8 a. m. to 7 p. m., and employed sights varying 
from 139 to 3(i9 meters in length. The average length of sight used in the morning work was 218 
meters (715 feet), while that of the afternoon work was 263 meters (863 feet), or 20 per cent longer 
than morning sights. The average error of the morning determination of the circuit length was 
—0.85 meter, or —1/1901, while that of the afternoon determinations was +0.60 meter, or +1/3185. 
The average uncompensated error of the forenoon work was —0.38 meter, or 1/5834, while that of 
the afternoon work was +0.05 meter, or 1/42630. This remarkably small error of afternoon work 
is, of course, accidental, but it is the writer's experience that seeing conditions of the air are much 
better in the afternoon than in the forenoon, both for stadia work and for pointings in measuring 
horizontal angles. 

The largest error in morning work was when half-interval sights of 309 meters in length 
were employed, at 9 o'clock. This gave an error of —2.77 meters, or — 1/SOO. Full-interval 
measurements using shorter sights at the same morning hour, and under less favorable 
circumstances, gave very much better results. Thus, one using 139 meter sights gave accuracy of 
1/2091; one using 201 meter sights gave accuracy of 1/2519; one using 222 meter sights gave 
accuracy of 1/2217; one using 277 meter sights gave accuracy of 1/2170. This uniformly small 
error indicates the greater reliability of the shorter length sight, which fact has also appeared 
from the previous discussion. 

The largest error of the afternoon determinations was the one using the same long half- 
interval reading of 3f59 meters, which at this time, 5 to 6 p. m., gave an error of +1.80 meters, 
or 1/1185. 

As previously stated, the sun was unobstructed on all the streets except D street. This 
street, until about 8.30 a. m., was completely shaded. After that time the sun struck the ground 
at frequent spots, increasing in number and area, till at 11 a. m. the whole street was exposed to 
the sun. After 2 p. m. the sun shone upon it only in spots, and after 4 p. m. tlie direct suidight 
was entirely cut off by the trees. 

The result of the thirteen different measurements of this street is in striking contrast to those 
obtained on the other three streets. Thus, while the average error of a single measurement on A, 
B, and C streets was 1/3340, 1/1977, and 1/2065, respectively, the average error on D street was 



* See flesoription of this base line iu footnote, p. 427. 

t In this work four different and totally inexperienced rodinen were employed at dilferent times. With one 
exception tboy were not over 15 years of age, and though they wwa shown how to hold the rod, before trusting them 
with it, doubtless more experienced rodmen would have insured better results. 

} It should be noted that the computation of stadia measurements of these circuits was the same as though 
made in o straight line of length equal to thi? sum of lengths of the four streets forming the circuit. Computations 
were not made by latitudes and departtirea. 



UNITED STATES AND MEXICAN BOUNDARY. 239 

twice as large (1 1023). As every comlitioii affecting- the measurement of all four streets was 
exactly tlie snme. excepting this one matter of alternate bi Its of sun and shade on D street, the 
greatly increased error in measurement of this street seems justly attributable to this peculiar 
condition. 

At the time tiie Held work was done the effect of the shade was expected to lend greater 
accuracy to the measurements, but later study has shown that alternate belts of suu and shade 
give rise to air columns of different temperatures and hence of different densities. Such a 
condition of the air causes indistinct images, together with increased refraction of the rays of 
liglit. The first effect causes large accidental errors, and the latter large systematic errors. 

The total time spent in measuring the thirteen circiiits, a total of 18 miles, was fourteen hours, 
making the rate of about 13 miles per day of ten hours. A double stadia line, i. e., one with both 
foresight and backsight readings on each distance, could, with two rodmen, be measured in 
nearly as short a time. 

V. StMMARY OF Cl>^'CLUSI()NS. 

The above exiierimental data lead to the following conclusions: 

First. Unsteadiness of a terrestrial line of sight is made up of both vertical and horizontal 
vibrations. 

Second. The vertical vibrations are made up of two systems, one of large amplitude and slow 
movement and the other of short amplitude and relatively fast movement. 

Third. This vertical vibration may seriously affect the accuracy of any single stadia reading, 
but from its nature it must cause a compensating error, and therefore is of only secondary 
importance. 

Fourth. The time of maximum vibration is about the middle of the forenoon, or when the 
maximum difference of temperature between ground and air occurs. 

Fifth. Long sights (i. e., those whose intercepts about e(iual the length of the rod) should, 
either not be read in the hot parts of the day, or else should be read by half intervals on the 
upper part of the rod. 

Sixth. The vertical vibration is acci)mi)anied by ;in abnormal refraction in the stratum of air 
within 3 or i feet of the ground, which in all past work has caused large accumulating errors, 
thus limiting the accuracy of stadia work to about 1/700. 

Seventh. The engineer who is to execute the tield measurements should -himself determine the 
stadia interval in order to avoid the systematic error due to his personal equation. 

Eighth. In determining the interval, the length of sight on base line should t)e limited to the 
most common ones employed in the field work. 

A somewhat wide correspondence with experienced stadia engineers establishes the fact that 
at present scarcely two engineers agree as to the i)roper time of determining the interval. One 
writes, '-determine it in midday;'' another, "determine it in the morning;" another, "during a 
cloudy day," etc. If the conclusions of this paper are correct, all are individually wrong, and yet 
collectively right. The only correct way is to determine the interval during manij hours, and 
select such hours as will approximate as closely as possible to average field conditions. The degree of 
accuracy which will result in the field measurements will correspond closely to the degree of such 
approximation. 

The writer is aware that some experienced topographers will refuse to follow his suggestions, 
for the reason that in their opinion stadia measurements are sufiQciently accurate already. For 
many purposes this is doubtless true, but these engineers certainly do fail to see the widening 
tield of usefulness that would properly belong to the stadia method, when once its accumulative 
errors had been brought within proper limits. A large amount of expensive control, now rendered 
indispensable by present careless methods, could be advantageously omitted as unnecessary. 

The stadia method is such a convenient and economical one to use that it would seem a step 
in the direction of progress to give the method increased accuracy, especially as this can be done 
at so little expense. 

The chief objections to the added care which is required in the original interval determina- 
tion, and also to any subsetiuent determination made necessary by a decided change in field 
conditions, will doubtless be the cost of repainting the rods in the latter case and the cost of 



240 UNITED STATES AND MEXICAN BOUNDARY. 

additional care in both cases. The first objection will be eutirely removed by not incorporating 
tbe interval in the rod, as is at present so generally done, but instead, using rods divided into 
standard units of length, and then computing true distance by means of an interval factor. By 
means of a table such computations can be made very quickly. All the measurements discussed 
in this paper were thus computed. This point is very ably discussed by Mr. J. L.Vau Ornum, of 
Washington University, in a paper on stadia work read before the American Society of Civil 
Engineers at its summer convention of 189.5. He names the following as some of the disadvan- 
tages of the i)resent method as compared with the method in which an interval factor is 
employed : 

First. Subsequent tests of interval can not be made without the expense of repainting and 
regraduating the rod. 

Second. Rods can not be Interchanged among transits. 

Third. Old rods can not be used with new transits. 

Fourth. Eods can not be used in leveling without computing the necessary correction. 

Fifth. Leveling rods can not be used in stadia work. 

Sixth. Observers with different personal equations can not use the same rods without 
causing systematic errors in the work. 

The disadvantages of the present system seem so evident that the adoption of the interval 
factor system seems only a question of the time necessary to " teach old dogs new tricks." 

The second objection to using proper care in determining the stadia interval is more ap[)areut 
than real. Increased accuracy of any work usually involves increased expenditure of care or 
money, or perhaps both. Tlie real question is, Will the results of such increased care justify the 
increased cost! It has been seen that such care prevents, in a great measure, the large 
systematic errors which up to the present time have confined the use of the stadia method within 
narrow limits. On some surveys with which the writer is acquainted the cost of the steel tapes 
worn out in making measurements where the stadia method might have been employed has 
exceeded either the cost of repainting rods or of the increased care of interval determinations. 
Again, it should be noted that in surveys extending over a year or more, and furnishing frequent 
triangulation or steel-tape checks on the stadia measurements, each check may be used as an 
interval determination, and the average of a number of such determinations would give tbe very 
best value for the interval to be used in future, without the expense of an extra dollar or of an 
extra hour of time. 

The foregoing report is hereby attested by the signatures of the members of the United 
States section of the International Boundary Commission. 

Signed November 25, 1896: J. W . Barlow, 

Colonel of Etiglncers, U. S. A. 

Signed October 1, 1896: A. T. MoSMAN, 

Assistant, Coast and Geodetic Snrvey. 

Signed November 25, 1896: D. D. Gaillakd, 

Captain of Engineers, U. IS. A. 



RE0e7« 



